Ohtar

The squire of Isildur. One of only three survivors of the Disaster of the Gladden Fields, Ohtar rescued the shards of Elendil's sword, Narsil, and brought them safely back into the North.

On the name Ohtar, Tolkien writes:

Ohtar is the name only used in legends; but it is probably only the title of address that Isildur used at this tragic moment, hiding his feelings under formality. Ohtar 'warrior, soldier' was the title of all who, though fully trained and experienced, had not yet been atmitted to the rank of roquen, 'knight'. But Ohtar was dear to Isildur and of his own kin.

Unfinished Tales, The Disaster of the Gladden Fields, note 17.