I would say yes, purely based on that Shirou has a Reality Marble (which essentially is/was what they replaced the RM's for Idea Blood in the Tsukihime Remake)

frenze said in comment #2630009:

I would say yes, purely based on that Shirou has a Reality Marble (which essentially is/was what they replaced the RM's for Idea Blood in the Tsukihime Remake)

Well no, Reality Marbles were not an Ancestor standard ability. They had no standard ability till remake with Idea Bloods.

Also key detail, what Arach gives you actually *overwrites* your soul with the framework of someone else's(An Ancestors) not just "appends".
She speaks of taking it in as something that requires a great meaningful sacrifice from the person. Every dose is a death, and with that rebirth.

TLDR Unlimited Blade Works will probably get completely torn out of Shirou(likely replaced by something new but not relevant), surviving the process requires not just mental fortitude but the will to sacrifice that, he must give up his life as a sword and hero, he would simply die otherwise
It has nothing to do with your strength -in the first place the injections were designed for weaklings-, merely your will, not just willpower but will to *change* and honestly Shirou's too stubborn for that(without appropriate motivation in a vacuum at least). He'd fight against the injections and probably shatter his soul in the process

RustyDive132 said in comment #2630184:

Well no, Reality Marbles were not an Ancestor standard ability. They had no standard ability till remake with Idea Bloods.

Also key detail, what Arach gives you actually *overwrites* your soul with the framework of someone else's(An Ancestors) not just "appends".
She speaks of taking it in as something that requires a great meaningful sacrifice from the person. Every dose is a death, and with that rebirth.

TLDR Unlimited Blade Works will probably get completely torn out of Shirou(likely replaced by something new but not relevant), surviving the process requires not just mental fortitude but the will to sacrifice that, he must give up his life as a sword and hero, he would simply die otherwise
It has nothing to do with your strength -in the first place the injections were designed for weaklings-, merely your will, not just willpower but will to *change* and honestly Shirou's too stubborn for that(without appropriate motivation in a vacuum at least). He'd fight against the injections and probably shatter his soul in the process

Before the remake, having a RM (or the abilty to have one) was a big indication on how far you would reach (potential) on the dead apostle ladder (it's one of the reason's why Satsuki Yumizuka skipped the early stages and went straight to dead apostle). You are right that not every Dead apostle ancestor had one, it was however expected for those of rank 10 and stronger except for that one ancestor who was over 5000 years old and didn't had one (old Tsukihime). The remake kinda removed RM's in favor for Idea Blood and made it a potential ability for all Dead apostle's (since they both work on a similar premise). I'm pretty sure Satsuki in the remake is going to have a Idea Blood instead of a RM. Of course Arach injections work differently than developing your own Idea Blood, and as you said it was designed for people who never had potential to begin with. Shirou would probably had a better time if he was bitten in the normal way rather than with Arach injections. Altough the latter cannot be completely ruled out either since Archer Alter exists (and probably any HF variant of Shirou?).

frenze said in comment #2630285:

Before the remake, having a RM (or the abilty to have one) was a big indication on how far you would reach (potential) on the dead apostle ladder (it's one of the reason's why Satsuki Yumizuka skipped the early stages and went straight to dead apostle). You are right that not every Dead apostle ancestor had one, it was however expected for those of rank 10 and stronger except for that one ancestor who was over 5000 years old and didn't had one (old Tsukihime). The remake kinda removed RM's in favor for Idea Blood and made it a potential ability for all Dead apostle's (since they both work on a similar premise). I'm pretty sure Satsuki in the remake is going to have a Idea Blood instead of a RM. Of course Arach injections work differently than developing your own Idea Blood, and as you said it was designed for people who never had potential to begin with. Shirou would probably had a better time if he was bitten in the normal way rather than with Arach injections. Altough the latter cannot be completely ruled out either since Archer Alter exists (and probably any HF variant of Shirou?).

I don't think the RM=Potential thing is true? Roa had an RM and was like, not really on the level of an Ancestor, he was somewhat counted as one cause he's a pain in the ass, not cause he was strong enough. So we have a definite weaker DA with an RM

Ciel in OG theorizes instead that Satsuki's strong compatibility with vampirism is due to her nature as a Psychic, with no knowledge of her breath of abilities, she never ties it to an RM. It's important to note you can develop an RM(Shirou) but to be a Psychic by definition is to have "natural aptitude for the Supernatural from birth"

And yes Shirou does have the chance of surviving it, provided the conditions align, which is why I brought up Potential Motivation but it is difficult. Mind of Steel Shirou gets the closest but even he's Pushing it(he's already considered a Bad End)