The 50th suit of armor developed by Tony Stark. It was first deployed when Iron Man's MK XLIX armor was stolen from him by M.O.D.O.K. for the Red Skull.
While its design is similar to the Mark XLIX, its energy input it's far greater.
Alternate Reality Versions
Reality warped by Squadron Supreme (Earth-TRN524)
In this reality, created by the Squadron Supreme when they used the Reality Stone, Iron Man and the rest of the Avengers were turned into villains. Iron Man's armor was colored black and gold. It was destroyed when Iron Man sacrificed himself to save the Avengers from Nighthawk.
- During the episode "Guardians and Space Knights" Tony surrendered himself to Galactus and became his herald. By becoming his herald Tony got the Power Cosmic infused with himself and his armor which turned dark yellow with an aura. Tony used the Power Cosmic to trick Galactus into devouring a planet with an unstable uranium core and send him into a long slumber. Later Tony lost the Power Cosmic and his armor turned into its regular powers and coloring.
- 94 appearance(s) of Iron Man Armor MK L (Earth-12041)
- 36 image(s) of Iron Man Armor MK L (Earth-12041)