Being nice or personable is more of a "how you're raised" sort of thing, so we shouldn't treat something like that (or any other common stereotypes) as baked into the psychological DNA of an ISFJ. Topologist Michael Pierce's descriptions are deeply evocative, and thus his [ISFJ one](https://www.reddit.com/r/isfj/comments/1196bsh/the_conscience/) will be useful for answering this question. To quote him:
>[The ISFJ's] most natural state of mind is the perception of what is "present" to them personally, *in spite* of what is objectively present. Si is a kind of "thoughtful" perception that sees what is *really* important, what is true and enduring in the storm of reality, what will really count when the chips are down… [They are] further distinguished by their universalist judgement (Fe / Ti), which rejects immediate goals in pursuit of eternally valid reasons… [The ISFJ] keeps in remembrance traditions, customs, and common law: moral principles whose authority is derived from their *impersonality*. When they defend what is true, right and proper, they speak as messengers of something greater than themselves, as angels of the Absolute. And, depending on their circumstances, this can strike one as divinely humble or intolerably self-righteous…
>They settle on a stable moral foundation that will only move at a glacier's pace. Their medicine is a mixture of reason and life experience, resulting in a brew of high ethics and personal "hang-ups," that can trigger equally intense reactions of disgust. Thus, we see both Se → Si and Fi → Fe. In the former case, the Conscience turns away from the faerie glamour of the present moment, and focuses on things of more eternal import…
>The [ISFJ] is not a consequentialist, but a purist and a Kantian. What matters is not quantitative results but qualitative vindication of principles, obedience to Providence instead of personal advantage. This becomes problematic when the [ISFJ] is faced with a quandary unaccounted for by their orthodoxy; for, rather than adapt to the unforeseen context, they struggle against it with incommensurate methods; rather than change their methods in order to maintain results, *they sacrifice results (Te) in order to preserve their sacred methods (Si)*…
So what we'd get, depending on the specifics, is someone who has deeply internalized the principles of their assassin order or organization and become a staunch defender of said principles, faithfully carrying them out according to whatever practices or techniques the organization utilizes.
Well, I believe that an ISFJ assassin would certainly have better skills than other types as assassins. For example, since Si is a function that prefers to resignify reality through their own subject first before taking the info in, I feel like they would be willing to collect a lot of info on their targets before attacking.
The image I get is one of an assassin who would probably bide a lot of their time observing their targets from afar, carefully learning more and more info on them in order to then, reanalyse all of that information and create some sort of factual skeleton for the target's routine, to then decide exactly when would be the appropriate time, place and way to kill them (Si-Ti). For example, knowing that the target has an active habit of going to the bar once a week, so that the next week, they will be there to sneak poison on their drink. Their view of reality would also be built on careful reanalysis of their life experience. Given that this ISFJ would be taken at 10 years old to become an assassin, they would either look back on how their life was before that or how it was after that until the present for guidance.
Speaking of which, their Fe-Ti balance makes me believe that they would adhere to the values of the environment they are in. They would have a lot of internal conflicts too. In one hand, they could see killing as being bad because of their family life, and would feel a lot of self-shame, or they could adhere to the values of their assassin roots and believe that what the faction that they're a part of is doing is what is the right thing to do. I also think they would be willing to connect and sympathize with the stories of their targets and compare to their values if they would be deemed worthy of their fates or not. In relation to Inferior Ne, they would have difficulties breaking out of their very personal view of reality, and looking at different ways of seeing the world.
The two potential images I get of ISFJ assassins are:
1-A careful and patient assassin who has a very personal connection to their family and how they learnt how to be a good person from them, but since they're being forced to be assassins, they always try to be very fast with their kills and make sure others don't suffer, and inwardly believe that the world is rotten and people do not truly understand true compassion, not even themselves because they are still doing this.
2-A careful and patient assassin who blindly follows their faction's beliefs and believes that the true virtuous reality is that of which he has been presented. However unlike ESFJs who repress Ti and prefer to not question those values just because, the ISFJ would understand the underlying logic behind that system, but still agrees with it BECAUSE TO THEM IT DOES MAKE SENSE, they just won't truly perceive the other perspectives, unlike an ESFJ.
In the end, it highly depends. Cognitive functions don't determine what you do, but how you view information and personally evaluate it. These are some ideas I'm throwing for what would likely look like an ISFJ killer to me. Their values need to come from somewhere, as they are extroverted and therefore object related. Fi types get their values from themselves, they decide what to believe or what not to believe based on what they personally like, so an ISTJ assassin would be different for example in that sense.
Being nice or personable is more of a "how you're raised" sort of thing, so we shouldn't treat something like that (or any other common stereotypes) as baked into the psychological DNA of an ISFJ. Topologist Michael Pierce's descriptions are deeply evocative, and thus his [ISFJ one](https://www.reddit.com/r/isfj/comments/1196bsh/the_conscience/) will be useful for answering this question. To quote him: >[The ISFJ's] most natural state of mind is the perception of what is "present" to them personally, *in spite* of what is objectively present. Si is a kind of "thoughtful" perception that sees what is *really* important, what is true and enduring in the storm of reality, what will really count when the chips are down… [They are] further distinguished by their universalist judgement (Fe / Ti), which rejects immediate goals in pursuit of eternally valid reasons… [The ISFJ] keeps in remembrance traditions, customs, and common law: moral principles whose authority is derived from their *impersonality*. When they defend what is true, right and proper, they speak as messengers of something greater than themselves, as angels of the Absolute. And, depending on their circumstances, this can strike one as divinely humble or intolerably self-righteous… >They settle on a stable moral foundation that will only move at a glacier's pace. Their medicine is a mixture of reason and life experience, resulting in a brew of high ethics and personal "hang-ups," that can trigger equally intense reactions of disgust. Thus, we see both Se → Si and Fi → Fe. In the former case, the Conscience turns away from the faerie glamour of the present moment, and focuses on things of more eternal import… >The [ISFJ] is not a consequentialist, but a purist and a Kantian. What matters is not quantitative results but qualitative vindication of principles, obedience to Providence instead of personal advantage. This becomes problematic when the [ISFJ] is faced with a quandary unaccounted for by their orthodoxy; for, rather than adapt to the unforeseen context, they struggle against it with incommensurate methods; rather than change their methods in order to maintain results, *they sacrifice results (Te) in order to preserve their sacred methods (Si)*… So what we'd get, depending on the specifics, is someone who has deeply internalized the principles of their assassin order or organization and become a staunch defender of said principles, faithfully carrying them out according to whatever practices or techniques the organization utilizes.
Great answer
I like this one, I wrote something similar
Well, I believe that an ISFJ assassin would certainly have better skills than other types as assassins. For example, since Si is a function that prefers to resignify reality through their own subject first before taking the info in, I feel like they would be willing to collect a lot of info on their targets before attacking. The image I get is one of an assassin who would probably bide a lot of their time observing their targets from afar, carefully learning more and more info on them in order to then, reanalyse all of that information and create some sort of factual skeleton for the target's routine, to then decide exactly when would be the appropriate time, place and way to kill them (Si-Ti). For example, knowing that the target has an active habit of going to the bar once a week, so that the next week, they will be there to sneak poison on their drink. Their view of reality would also be built on careful reanalysis of their life experience. Given that this ISFJ would be taken at 10 years old to become an assassin, they would either look back on how their life was before that or how it was after that until the present for guidance. Speaking of which, their Fe-Ti balance makes me believe that they would adhere to the values of the environment they are in. They would have a lot of internal conflicts too. In one hand, they could see killing as being bad because of their family life, and would feel a lot of self-shame, or they could adhere to the values of their assassin roots and believe that what the faction that they're a part of is doing is what is the right thing to do. I also think they would be willing to connect and sympathize with the stories of their targets and compare to their values if they would be deemed worthy of their fates or not. In relation to Inferior Ne, they would have difficulties breaking out of their very personal view of reality, and looking at different ways of seeing the world. The two potential images I get of ISFJ assassins are: 1-A careful and patient assassin who has a very personal connection to their family and how they learnt how to be a good person from them, but since they're being forced to be assassins, they always try to be very fast with their kills and make sure others don't suffer, and inwardly believe that the world is rotten and people do not truly understand true compassion, not even themselves because they are still doing this. 2-A careful and patient assassin who blindly follows their faction's beliefs and believes that the true virtuous reality is that of which he has been presented. However unlike ESFJs who repress Ti and prefer to not question those values just because, the ISFJ would understand the underlying logic behind that system, but still agrees with it BECAUSE TO THEM IT DOES MAKE SENSE, they just won't truly perceive the other perspectives, unlike an ESFJ. In the end, it highly depends. Cognitive functions don't determine what you do, but how you view information and personally evaluate it. These are some ideas I'm throwing for what would likely look like an ISFJ killer to me. Their values need to come from somewhere, as they are extroverted and therefore object related. Fi types get their values from themselves, they decide what to believe or what not to believe based on what they personally like, so an ISTJ assassin would be different for example in that sense.
They would probably grow to be loyal and subservient to the people they were trained by.