Teostra's control over the Fire Element is speculated to come from his two curved horns. The relationship between the two is unclear, but hunters can cripple the monster's ability to produce a fire aura if they can manage to destroy them. As part of a sexually dimorphic species, Teostra is the male counterpart to the Lunastra, though the two are rarely seen together.
Lunastra is colored blue as opposed to Teostra who is red. Her horns are flatter and wider, making a sort of crown.
Rare Male Variant
When Toa Tesukatora enters rage mode, it'll cause a blizzard that will slowly freeze anything that isn't moving continuously.