Hell breaks loose in Hallownest (Doom slayer reader x hollow knight)

This is being done as a thank you for reaching 10k reads on my titanfall story but without further ado, here we go:

The UAC's most remarkable discovery was in Hell's Kadingir Sanctum. Surrounded by nearly impassible terrain, the team discovered a sealed tomb - its entrance and walls covered in protective runes and imprisonment incantations. The tomb revealed many artifacts, including the Praetor suit. Most notable, however, was an enormous sarcophagus, bound to the bedrock center of the tomb with thick chain iron bands - seemingly anchored to prevent anything from getting in or out. It was believed this sarcophagus must hold a rare or powerful demon, but when opened, it revealed the body of a man. Unrelenting; unforgiving: driven by a rage that cannot be contained. The Doom Slayer has been to Hell and brought it to it's knees. He has no records, and he vanishes as quickly as he appears. The few witness accounts available detail a ruthless killer...

However in his crusade, he's betrayed by someone he thought an ally, and is transported across the dimensions, and finds himself in a strange new world. How will he handle his new surroundings, and how will he face a new threat, one which even he has never seen before?