"Outer Entity Nyarla" can assist in the summoning of this card when used with "Rank-Up-Magic" cards by having it attach a Dragon-Type monster from your Graveyard to it using its effect as well as manipulating its Rank.
Use "Mist Body" on your opponent's attack position monster and this card's detach effect to attack multiple times for damage to their Lifepoints.
This card is easily Summonable in "Hieratic" Decks and "Hazy Flame" Decks which heavily use Level 6 monsters.
In addition, "Hazy Flame" decks can make excellent use of this card, given that the archetype (through "Hazy Pillar") has a strong emphasis on restoring and accumulating Xyz Material.
"Hazy Flame Sphinx" and "Hazy Flame Peryton" can make creating a 5 XYZ "Chaos Chimera Dragon" easy, but keep in mind that you cannot Xyz summon "Chaos Chimera Dragon" while you control 1 or more face-up copies of "Hazy Flame Hydra", as it restricts your special summons to FIRE monsters only.
Utilizing "Xyz Unit", you can further increase this monsters Attack by an additional 1200 ATK, plus the opportunity to use it double-attack effect once without detaching Xyz material.
While this monster's Xyz Material-gaining effect is costly, it can be extremely effective both in and against Graveyard-heavy decks. You can reuse a spent card from your own Graveyard, or get rid of a card from your opponent's Graveyard, or even place a useless card from the opponent's Graveyard onto their Deck to make them waste their Draw Phase.
When this monster's Xyz Material is depleted, such as after its last attack or if it was re-Summoned after being destroyed, you can also use "Numbers Overlay Boost" to restore its ATK and Xyz Materials right away.
While it is typically better to have more life points than your opponent, there are advantages to being able to lower your life points at will. Since this card's third effect manipulates your life points, you can use the effect to eliminate an opponent's advantage over you due to you having more life points, or give yourself an advantage by using effects that require you to have lower life points than your opponent. For example:
You have more life points than your opponent. You use Number C5: Chaos Chimera Dragon's third effect to make you life points lower than your opponent's. You then equip the monster with "Unstable Evolution", essentially granting it an extra 2400 attack points. (Even when your opponent's life points drop below your own again, Unstable Evolution will make Number C5 1000 points stronger than it would be without it (like an extra Xyz material), though it will take up a spell/trap zone.
You can use "Magical Scientist" to Special Summon 3 or more Level 6 Monsters to overlay into this card.