Obakan
Personally, Okakan is my favorite Classic 5* purple for a first rainbow 5* 2.60 team. He has fast mana speed Splash damage ( good for questing and defense teams), he has fast mana speed reflect damage ( nice for raiding and titans ).
My wife loves him raiding:
5* Synergy with 4* / 5*
This is a great example of 5* synergy with 4* heroes.
His low defense increases reflect damage, Rigard can heal 42% and Cleanse him, Tiburtus lowers enemy defense stat so Obakan does more damage ( physical & special skill), Cyprian adds reflect damage to two others, while Hansel ( with fast mana speed) can protect himself with special skill defense and the whole team with special skill control.
Edit:
Her defense team is all 5* 4.80 heroes.
Ameonna
Ameonna is designed to be an anti- reflect damage hero. I am taking her to 4* 3.60 to go with my Rigard 4* 4.70 and 4* 3.60 purple heroes ( 2nd Rigard, Tiburtus, 1st & 2nd Sabina, still no Cyprian ).
4* Purple in hand
If I don’t get Proteus soon, I might take Ameonna to 4* 4.70 to unlock Sorcerer ( Delay, a good match with her Special skill) or Tiburtus to 4* 4.70 to unlock Ranger ( Pierce is unreliable versus reflect damage, unlike Ameonna, but nice against defense buffs especially protection from purple).