
See those big white tendrils roots on the map. That's how big of their Quintillion number fleet is and this is just the scouting party. The rest of the fleet have already consumed some galaxies they won.
The Tyranids are a dangerous race that only desire to become strong consuming all organic life including the planets themselves. After they take every last resource there it leaves the planet they invaded a rockey barren atmosphere less world. The Tyranids main strategy is to use overwhelming numbers. If that fails they bring in the more highly intelligent Tyranids to make them more smarter with their telepathic hive connection to human reasonable levels of tactics.
When an organic lifeform is consumed they are converted mind reborned as a Tyranid lifeform to serve the supposed goddess like entity The Hivemind for the rest of their lives with no memory recollection at all. The devoured organic lifeform dna becomes a genetic material to make the tyranids stronger. They consume an organic who have powers they get their powers. However they don't just use sentient lifeforms to multiply their numbers the organic life they stole on the planet increases their population higher billions more.
Tyranids are immune to disease and have the psychic collective power The Shadow of The Warp to block the warp itself from interfering and cause fear to all psychics listening to them. They make sure escaping them from another part of outer space using the warp to travel will not be easy.
The Tyranids don't make allies with any hero or villain faction. They are there to consume them in any organic life filled planet they fight on in the multi-universe.
LOTM: The Angels Return[]
While the Disney Angels and their friends were observing an agricultural planet, they were suddenly attacked by a swarm of Tyranids that seemed unbeatable! Fortunately, Imperial Guards, Ultramarines and Salamanders came and added their firepower and strength!