Zekenation

TYFC I could hardly stop myself from laughing while reading this

it's complicated as it does work on poison and possibly anything that isn't natural. the heart virus is natural so it can't be cured, but being effected by poison it works

yet she can still find a way to ruin all his plans. there's a reason why they are the MC of the story not to mention they can technically be part of a massive group of immortals. from what we can tell the travelers aren't really warriors but closer to seasoned adventurers. there's a big difference between the 2

he made up the prophecy & screwed over Morgan making the whole situation worse

not in this case. Fate Merlin doesn't have the power to see the future he can only see anything in the present time. it's the only reason he is considered a candidate for Grand Caster. Even though he isn't dead, he can still find loopholes. in Babylonia, he was able to be summoned as despite not being dead, he was also not even born yet, so he was able to leave his tower & travel to the past & help

so basically, he is pulling a dick move and is trying to baby trap the traveler. he is messing with something dangerous if he thinks it will work. if the travelers are capable of traveling to countless worlds of their own power & are possibly even older than Teyvat itself it wouldn't be wise to do this

A breakdance battle with a doom beast is so chaotic bet he might even get a few Aeons attention

TYFTC

still overkill they can seal him away for eternity