Raven Tome Mage?

Of each color, I say the best ones are:
Blue:Male Robin (easiest to build)
Red:Sophia (Henry has a bit more def, but she has more atk and res in exchange for speed)
Green:Boey (Has the highest def out of these three I believe)

M Robin, F Robin, Cecilia, Boey, and Sophia are some common ones I could think of. If you have Lyon, he also runs a prf raventome. In reality, any mage with good physical bulk (over 60 hp+def preferably, but lower could be ok as long as it’s not below 50) and decent attack can run a raventome adequately.

M Robin is a great choice for a raven tome unit

M Robin is a great choice for a raven tome unit

Lyon gets my vote. He's an excellent raven tome with minimal SI needed.

Blue: M!Robin
Red: Sophia, Henry
Green: Boey, Cecilia

Proud owner of a +def Boey. Slap QR3 or Bowbreaker on him and he will pretty much always take 0 damage against a physical colorless unit.