High enough levels of radiation won't kill you by cancer or tumors, they will legit cause enough cellular damage to put someone into a coma like Elephant's foot in chernobyl.
Garou's passive radiation was killing fish through water, incapping superhuman heroes including zombieman from tens of meters and Blast stated that if Silverfang came within melee range from him he would die instantly. (While the virus survived a nuke it was apparently far from the blast's epicenter? Not sure how much radiation that would be.)
Nuclear fission fist would be getring hit by a nuke, but much closer wich is higher than his passive radiation and GRB is on such an absurd level it would shave the atoms of someone's body away. Specially since he creates a black hole before using it wich spawns from himself, shielding himself from viruses.
Obviously it's either a who attacks first,Alex with virus gas and Garou with nuclear fission or GRB. Or a stomp if the blacklight virus can't survive the passive radiation. Does the airbone virus need some kind of entrance or can it penetrate skin or whatever cosmic shell Garou has in his body?
And Alex Mercer doesn’t really have cells, he’s made of nothing but viruses, so causing cellular damage doesn’t mean that much against him. Plus, he has already dealt with the effects of anti-viruses such as Bloodtox just fine (which not only destroys Blacklight Viruses, but also causes
necrosis in Infected tissue if what I’m reading from Alex Mercer’s profile is correct). His feat of being unaffected by the nuclear explosion’s radiation is just the icing on the cake, but that doesn’t matter much either way as… Well, he doesn’t really have cells in the first place.
All of the passive radiation killing fishes, heroes and such are all from killing multicellular organisms, and Zombieman has far inferior regenerative capabilities to Alex Mercer’s if we were to compare their Regeneration feats - I doubt Garou’s passive radiation has feats of killing beings that aren’t made from cells; though even if he does, I have yet seen any feats where his passive radiation has dealt with Mid-High Regeneration.
Even in the worst place scenario in assuming that Alex Mercer is
somehow affected by radiation, Radiation in this site is assumed to only ever deal with
biological Regeneration of up to Low-High - and Alex Mercer has Mid-High
overall regeneration (his Regeneration being listed as Low-High in his profile is due to his
regenerative speed varying based on the reserves of excess biomass he has, with having little to no excessive biomass reserves resulting in him regeneration very slowly similarly in a Low-High manner but still healing, but his
regenerative extent is still Mid-High even with little to no excess reserves of biomass), so it’s nothing that Alex Mercer can’t eventually regenerate from.
And as, for whether the virus needs some kind of entrance - this very same virus from the gasses was capable of bypassing the air filters of gas masks, and has shown to even get someone sick and vomiting out blood while they’re in Hazmat suits… It can basically even infect someone in. Hazmat. Suits.
So I doubt the Blacklight Virus from the gasses would do much worse in bypassing Garou’s shell on his body, especially when it seems to be implied to made of physical materials when even characters far weaker than him was able to physically interact with him (so he’s definitely not intangible or incorporeal in his 4-A key either), when even materials built to shield contaminants failed to hold up against the Blacklight Virus.
Also, while Garou would need to use GRB to constantly punch all around him to shield himself from the Blacklight Virus and that he’s better off at using his portals to escape it, the prior knowledge definitely makes it too difficult on Alex Mercer and would make this be nothing more than a mismatch as long as Garou has prior knowledge.
