If we're talking about Awakened Champs then Psylocke. She was my first 4* (got her both times in her last arenas while still in Beginners bracket). If we're talking about duping a champ from a crystal, then Iceman. Both are 2 of my top champs atm.
My First 4* was BP and it took two years to dupe him, but my next was War Machine and got him again in the next for my first dupe. Haven't used much of either since questing lower level.
Ghost Rider was my first 4*, first duped 4*, and first to R2, R3,R4, and R5. I still use him a lot, especially in AQ or as an AW attacker, as well as arenas and general questing.
Comments
when the Rank Down tickets came in March, i took her from r4 to r3. and since then she is only used as arena fodder.
Now have him again awakened at rank 3