Both Cee and Jinpachi are good options to run with lightning main if you want to use the ay 3rd/samui duo.

Jinpachi gives you for 3 round an ignition mystery and a 2nd standard attack for ay + clears 1 layer of debuff on him and can be shielded with root of warrior.

Cee gives you a very solid healer that removes debuffs and shields on round 2 on whoever is not lightning + blinds with standard attack and gives you back 100% of the chakra used by your enemies, so, even if samui dies, you still have a big chakra generator.

It's up on the usual enemies you fight against to choose which one to select.