easiest character for prismatic trials?

[charlie white]

just need the achievement

[Ninja Zyborg]

just wait for an easy prismatic trial

[Chaoz]

If you have power mode, auto-nailgun MUL-T could work, but if you don't, I managed to beat one trial with double rebar

[Ver-Anna]

It's viable on literally every character. The only reason one character would be significantly better is if the artifacts and/or items in the trial favor 1 character

TLDR: depends on what the rolls are

[mldb88]

If you're going for the achievement for it, doing a no-hit run on Mercenary would kill 2 birds with one stone, but as for just clearing it, whatever character you're best with should be fine. Since the item rolls/modifiers change from trial to trial it really just depends.