The word “reckless” runs through this entire story!
…
After transmigrating to the Marvel Universe,
“Ding! System binding complete. Welcome…”
The protagonist: “Shut up. I want to go home.”
“Ding! Ultimate mission issued: A Warrior’s Glory
Mission requirements: Die in a battle where you give it everything you’ve got
Reward: Return to your original world”
…
Tempted by the prospect of going home, a berserker roams the Marvel Universe, searching everywhere for a chance to die in battle.
But…
The protagonist looks at the pile of supervillain corpses and scratches his head in confusion.
Why can’t I die?
(Just treat any changes to the timeline and plot as part of a parallel universe.)