Player Customization

Player Customization is a feature found in Quake Champions and Doom Eternal. In which the players can change their appearances. There is even lore surrounding this and why it occurs within the canon...

Background
In its analysis of this abberation, VEGA observes ephemeral distortions within the fabric of reality: scrambled reflections of the physical world. As the Slayer interacts with this anomaly, a peculiar ripple in the anomaly's composition emerges, seemingly reacting to the Slayer's presence reflexively. The anomoly reshapes itself, calibrating itself to the Slayer, responding to his memory, ancestral, and memetic data, before utimately projecting itself onto the Slayer himself. These change his appearance to many different suits (from those he wore back in his time during Doom 1, to his time in Quake Arena/Champions etc).

This seems to suggest that the single slayer has lived many lives, and possibly across many realities. He has memories of these past lives that can be accessed via anomalies and time travel. This may also explain his use of 'extra lives'. There maybe 'one earth' but actions of the Doom Slayer and Hell may have changed the direction of that history several times creating new 'timelines'. Flynn Taggart may be a version of him one timelie, B.J. Blazkowicz a version from another, Marine from Doom3, yet another of his reincarnated lifetimes.