One of the most broken units for me as a beginner, much more then Aisha or Lapis or Elyse is Silvia. My Silvia is still at 0 Affection and level 34 while my other non cc blacks are lvl 80 with 100% affection or cc30 w 100%. Why? Cause she fucking doesnt need it. My other units acualy need that just to keep up with her performance at lvl 34 0%. I use her to gank even bosses i wouldve had trouble to gank on my nutaku account. 3006hp, 390 atk, 521 def, 15 mr with 50% dodge and magic attack at 20 cost without prince, teeny or skill (that lasts 2 minutes) buffs. No Affection and fucking level 34. Thats just op. Some might scream 'But Nero! She cant be healed!' and id say YES and thats awesome. No need to place her near any healer, she just heals her self with every attack!
She can get boosted by her own skill, prince and teeny and just that already puts her above 1.3k def and close to 1k atk with little to no investment besides skill level.