Level Melendor to 4* 3.60 AND Hansel to 4* 3.60,
Then Melendor to 4* 4.70,
Then Hansel to 4* 4.70
Melendor is a 4* healer with 42% heal all and a high attack stat, perfect for using Wu Kong ( see Notes ) against titans, raids, and war.
I ran Halloween event on autoplay for normal levels 1- 20, and have so far used autoplay up it to advanced level 5 ( waiting on World Energy) with Melendor, Grimm, Wu Kong, Scarlett, Rigard ( all 4* 4.70 ).
Leveling two 4* heroes to 3.60 takes the same XP as leveling one to 4.70, but 4* 3.60 are the most powerful heroes in the game using only farmable ascension items.
Merlin ( purple), Hansel ( green), & Gretel ( yellow) are the three 4* heroes that can stop special skills from firing & damage the enemy side three times if you can fill the target’s mana bar three turns in a row. This is much more useful in raids and war than against titans.
Hansel is the sole reason I am Gold/ Platinum Arena ( I swap every few hours).
For 4* green I leveled Melendor 4.70, Peters 3.60, Kashhrek 3.60 ( nice 4* center), Melendor 3.60, Hansel 3.60 ( in a single weekend as part with a rainbow team ), and now I am leveling Little John to 3.60.
Depending on heroes from Reflect green event, I will probably level Hansel to 4* 4.70.