A Guide to Fire Kings

I:P Masquerena Link 2 DARK Cyberse 2 non-Link Monsters During your opponent's Main Phase, you can (Quick Effect): Immediately after this effect resolves, Link Summon 1 Link Monster using materials you control, including this card. You can only use this effect of "I:P Masquerena" once per turn. A Link Monster that used this card as material cannot be destroyed by your opponent's card effects. ATK 800

Masquerena can play one of two roles in your deck:

She can act as an interruption during your opponent's turn - you Link Summon a card like S:P Little Knight or Knightmare Unicorn in order to remove a card on the field before your opponent could use it.

Or you could use her to strengthen a monster on your turn - for example, you can use her as Link Material to Link Summon [Borrelsword Dragon] to make it unable to be destroyed by both battle and card effects, making an already powerful card even stronger.

Keep in mind that she's a DARK monster - so if you plan to summon her with Amphibious Swarmship Amblowhale's effect, you need to make sure you aren't FIRE-locked by Promethean Princess, Bestower of Flames.