Todder accompanies Jon Snow on his expedition to Hardhome. During the battle that ensues after the arrival of the Night King, he attempts to dissuade Jon from staying behind to fight off the White Walkers, but Jon orders him to keep transporting wildlings to the ships. After the Night King summons a new host of wights, Toad pulls back to shore to allow Jon, Edd, Tormund and the last few fighters to jump aboard and escape the oncoming hoard and row away. Todder is then seen returning to Castle Black with Jon Snow, Eddison Tollett, Tormund and the rescued wildlings.
Todder was first mentioned in Season 1's "You Win or You Die", but he didn't appear on-screen until Season 3's "Mhysa". Even then, the actor wasn't identified by name to be playing Todder until Season 5's "Hardhome".
In the books
In the A Song of Ice and Fire novels, Todder is the son of a winesink owner. He is described as a short, ugly boy with an unpleasant voice. He has pig eyes, small and shiny. Instead of a Builder, Toad is made a Ranger. He's part of the group of friends that prevent Jon Snow from abandoning the Night's Watch when the latter flees to join Robb Stark on his march south to wage war against the Iron Throne.
On "A Dance with Dragons", Toad complains about Melisandre's preaching, that she calls the Seven and the old gods false gods, and made the wildlings burn weirwood branches. Later, Jon sends him to serve at the Shadow Tower.