Normal Summon "Overlay Sentinel" (its effect will change it to Defense Position), then Special Summon "Overlay Booster" (which will be in Defense Position), then you can Special Summon "Backup Warrior" from your hand and Xyz Summon a Rank 5 monster.
This card is great because it offers all Xyz Monsters an ATK boost until they leave the field without taking up Spell/Trap Card Zones (because it's a monster) or your Graveyard (because it banishes itself to use its effect).
Use this card's ATK-boosting effect on Xyz Monsters with lots of Xyz Materials for huge ATK boosts.
This card is surprisingly useful in "Hazy Flame" decks.
It has an easy special summon, so you can use it to tribute summon a level 6 FIRE monster.