Dad

Duke is the father of the Player character.

Bio
Duke and the Player, moved from Sinnoh to Katrian to start a new stage in their lifes after the mother died in an accident before the moving.

Role
In Pokémon Lux and Nox, Duke is the one who heals player's Pokémon in their house, he also gives gifts to the player, like the Shiny Charm or TM.

In post-game he could play a role in Ignis Arc.