This is because his hair (and just the hair) is defined as colourable. You can try assigning him no colour palette (go to <Color_Palette> tag in character.xtbl or character_definitions.xtbl and erase it),
or
if the game doesn't allow "no colour palette" to be black you will have to look through npc_color_palette.xtbl and see if there'sa "black" or dark enough palette. Otherwise you may have to create a new palette to match Dex's hair (if you use Voliton's table file editor, it will make a lot more sense; alternatively duplicate from <Palette> to </Palette>, edit the colours to be all 0. Finally make character.xtbl use it.)
or
if the game doesn't allow "no colour palette" to be black you will have to look through npc_color_palette.xtbl and see if there'sa "black" or dark enough palette. Otherwise you may have to create a new palette to match Dex's hair (if you use Voliton's table file editor, it will make a lot more sense; alternatively duplicate from <Palette> to </Palette>, edit the colours to be all 0. Finally make character.xtbl use it.)


