Second Best Purple Character?

There are 2 choices:

Aside from being Free and having a Scout event, which allows him to get more Z-Powers and getting more Stars to power up, Krillin also can also Regen his own HPs by 25% thanks to his main Ability, and his HP stat is decent. So, it's certainly more difficult to kill compared to other PUR characters. The problem? He's really weak physically, both his Strike ATK & DEF are really low.

Overall low-ish stats and very very high critical rate. The major problem here is he depends on luck, just like the whole Critical mechanic. Still, can be an interesting character and PUR doesn't have many choices anyway.

I'd say Krillin, because he's easier to develop.

If we include the new characters which will be implemented soon in the game then, Third form frieza would be the second best purple unit. He gets several bffs to blast attacks like SP vegeta and a 20% buff to strike attacks through his extra art. His stats are also pretty decent and the frieza force tag is getting several new supports in the new banner so he will have good synergy too