"This card is always treated as a Rank 1 monster." is not treated as an effect".
The "Cannot be destroyed by battle, also any battle damage either player takes from a battle involving this card becomes 0." effect is a Continuous Effect. (This effect is only applied during the damage calculation. Also, if the opponent's monster has lower ATK, the opponent's monster will be destroyed by battle.)
The "At the end of the Damage Step, when this card battles an opponent's monster: You can take control of that opponent's monster until the end of the Battle Phase." effect is a optional Trigger Effect. (This effect does not target, and cannot be activated if the opponent's monster is destroyed by the battle and sent to the Graveyard.)
The "If this face-up card would be destroyed by a card effect, you can detach 1 Xyz Material from this card instead." effect is a Continuous Effect. (Detaching the Xyz Material is not a cost. Also, this effect can be applied during the Damage Step.)