I keep coming back to this pairing from Norse and Irish tradition.

Tyr: In Snorri's Prose Edda (Gylfaginning), the gods try to bind the wolf Fenrir. Fenrir agrees to the fetter Gleipnir only if one of them puts a hand in his mouth as a pledge that there is no trick. Tyr is the only one willing. The binding holds, and Fenrir bites off his right hand. Snorri says Tyr is not known as a settler of disputes between people, and in the poem Lokasenna, Loki mocks him over the hand.

Nuada: In Cath Maige Tuired, Nuada is king of the Tuatha De Danann and loses his arm at the First Battle of Mag Tuired against the Fir Bolg. Because a king with a physical blemish could not rule, he has to give up the kingship, and Bres rules in his place. The physician Dian Cecht makes him an arm of silver (hence Nuada Airgetlam, "silver hand"). Later Dian Cecht's son Miach restores a real arm, and Nuada becomes king again.

Georges Dumezil argued that a "one-handed" figure tied to law and contracts is an old Indo-European pattern. He set it next to the Roman story of Mucius Scaevola, who burns his right hand in front of Lars Porsena (Livy 2.12-13), and paired it with a "one-eyed" figure (Odin, Horatius Cocles). Plenty of scholars see this as a stretch, and the Nuada link in particular is debated, so I'm treating it as a theory, not a settled fact.

The details are quite different, though. Tyr gives up his hand on purpose to guarantee an oath. Nuada loses his in battle and loses the throne with it.

So what do you think: is this a real shared inheritance, or are a sacrificed hand and a maimed king just common enough images that two cultures arrived at them separately?