Namor Visionaries by John Byrne Vol. 1 (Namor: The Sub-Mariner (1990-1995))
Collects Namor: The Sub-Mariner (1990) #1-9.

Namor, the Sub-Mariner! The world's first mutant! King of Atlantis! See one of Marvel's most iconic characters written and penciled by the talented John Byrne! As Namor finally learns the truth about his nasty temper, he faces the corporate threat of the diabolical Marrs' twins, tames the deadly Griffin, is sued for his attacks on New York and gets beheaded! It's Namor like you've never seen him before! Guest-starring Namorita, Iron Man and the Fantastic Four!