Rumiko Fujikawa first appeared in the pages of Invincible Iron Man Vol 3 #4 (May 1998) while Iron Man (Tony Stark) battles Firebrand on the island of Isla Suerte. The daughter of Kenjiro Fujikawa, the man who had taken over Stark's company during his stay in the Heroes Reborn universe, she begins to date Stark largely as an act of rebellion to parents who disapproved of Stark.

Rumiko's romance with Stark enjoys many highs and lows. She enjoys his jet-set lifestyle but finds he is often too obsessed with his work and does not pay enough attention to her. This fact is made even worse due to all the problems facing Stark in his career as Iron Man at this point, such as his armour temporarily becoming sentient and attempting to kill him, or the arrival of the Sons of Yinsen, a group dedicated to the memory of the scientist who helped Stark develop the original Iron Man armour. At one point she engages in an infidelity with Stark's business rival and enemy, Tiberius Stone. When Stark catches them together, the relationship ends. In remorse, Rumiko arranges for Stark to acquire sufficient stock in his old company that he can reclaim control of it.

Rumiko is murdered in Invincible Iron Man Vol 3 #87 (October 2004) when she is attacked by an Iron Man impostor named Clarence Ward.