The Master of Death is a dangerous title; many would claim to hold a position greater than Death. Harry is pulled to Middle-earth by the Witch King of Angmar in an attempt to bring Morgoth back to Arda. A year later Angmar falls and Harry is freed. What will he do with the eternity granted to him? Story begins 1000 years before LotR. Eventual major canon divergence.

He remembers being Harry Potter. He dreams of it. He dreams of the Great Other too, a beast of ice and death with eyes red as blood and an army of dead things. He is the second son of the king, but his fortunes change when secrets rather left in the dark come to light, and Westeros is torn asunder by treachery and ambition. Winter is coming, but magic is might. Very Abandoned

Since he's done the time traveling thing, it's only fair that Tsuna does the parallel world traveling thing too. At seventeen years of age, Tsuna is thrown into a world where Sawada Tsunayoshi disappeared at the age of seven and ten years down the line the Vongola is still undergoing succession issues. And the Undicesimo is the younger brother Tsuna never had. Sawada Tsunashige.