King Peregrin is credited with designing the impregnable box that the Shadow Demons were housed in.[1.2] However, the source of this information is a history book whose truthfulness is questionable.[a] Either way, Peregrin does not appear in the Hall of Heroes, so it is unlikely that he is the great hero.
Canny Tim was present for the Battle of Gallowmere and if he survived, it is likely that he would be involved in its aftermath. A history book does report Canny Tim's death at the Battle of Gallowmere.[1.2] However, the death described is the fate suffered by Sir Daniel Fortesque rather than Tim, calling the nature of the death, if not the death itself, into question. Canny Tim is also a member of the Hall of Heroes, thus satisfying the "hero" requirement.
After the Battle of Gallowmere, Captain Fortesque is stuck in the body of his heroic future counterpart. What he does immediately following the battle is unknown, making his involvement with the sealing of the Shadow Demons a possibility.