Colleen is the best healer for NB10 because she provides a strong heal, multi-hits, HP recovery block, attack break, and attack power buff.
You can also build Colleen on high speed to help heal better on the trash waves.
Grego is one of the best damage dealers for NB10 because he provides the top three most important skills: multi-hits, defense break, and attack speed slow.
His passive also makes him take less damage so you can focus on building him with more damage, his passive also gives him a huge damage buff if another team member dies which increases your runs reliability.
Rigel is amazing for NB10 for the same reasons as Grego, the only difference is his passive only reduces his chance to get crit.
Fuco is amazing for NB10 for the same reasons as Grego and Rigel, the only difference is his passive gives him a small HP shield.
Lucasha is one of the hardest hitting damage dealers for NB10 with a crazy amount of multi-hits.
She also provides a defense break on skill one and is very easy to build and skill up.
6. Shaina/Sabrina (Twins)
Shaina and Sabrina are amazing for NB10 because of the crazy amount of multi-hits and damage they can pump out. They also bring some important debuffs like Defense break, Heal Block, and Attack Break.
Shiana also provides an extremely reliable defense break and AoE defense break that will make clearing the waves much faster.
7. Teshar / Lushen
Teshar and Lushen are both great for AoE clearing the trash waves before the boss. They both also provide a really big damage leader skill.