Shiki Tohno may have his Mystic Eye of Death Perception, but All Might's One for All quirk gives him superhuman strength, speed, and durability that Shiki cannot match. Plus, with a guard score of 40, Shiki will have a hard time getting through All Might's defenses. Even if Shiki manages to see the line of death on All Might, it won't matter since All Might is too durable to be destroyed by a mere knife. All Might's California Smash attack also gives him a strong close-range option that Shiki doesn't have the means to properly counter. In this battle between the killer and the hero, All Might is the clear winner.