Colossus is a class in Eredan Arena that features dragon and titan-like heroes. They are also marked with an "SV" tag (similar with Ex tag) on the right side of their name. They have strength which is higher than most heroes, such as Panturien with 200 base strength.
Colossus heroes can only be obtained by playing and winning survival matches (no chest rewards for colossus heroes) with only one specific hero available per weekly cycle. 3 wins awards players with the card at Lv 1, 12 wins at Lv 2, and finally 30 wins unlocks the card at its max level.
Colossus heroes cannot be maxed out using F'eez like all other regular and Ex cards making them exclusively available in Survival Mode. Players who only manage to get the card at Lv 1 or 2 during one cycle will always be able to add gems to it when it is back in rotation by constantly winning its Lv 1 or 2 copies again.