Irys begins its life as a stone egg, sealed within a small underground temple in Nara village and guarded over by a family line named Moribe - local legend said it was the resting place of a demon called Ryu-Sei-Cho. (A character explains this name to be linked to Chinese mythology) A stone of unknown origin is said to keep the demon dormant as long as it's not moved.
A young girl named Ayana Hirasaka - left an orphan by the 1995 Gamera/Gyaos battle and blaming Gamera for her parent's deaths - entered the cave on a dare and moved the stone. In the process she and the latest son of the Mirobe line discover both the egg & an amulet, similar to the one that linked Asagi to Gamera in the first film. The egg later hatched, produced an infant Iris.
Ayana gains a link to the creature via the amulet and feels a kinship with the creature, stating at one point "Gamera killed its family too"; driven by total hatred for Gamera, she raises Iris (naming it after her dead pet cat) in hopes that it will become strong enough to kill him for her. It was shown to have an affectionate nature, but this is shown alongside the sinister way it eats and, later in the film, the woodland animals it leaves dead.
It is not long before Iris it attempts to merge with Ayana - and her actions show she's willingly letting it do so - by sealing her in a cocoon. Moribe discovers her and cuts her free. She is then taken to a hospital. While Ayana is gone, Iris grows kaiju-sized in the woods as it devours several villagers, including Ayana's adoptive parents and brother. Shortly, the monster grows into its adult form.
The Japanese Self-Defense Force quickly deploys and surrounds Iris as it sleeps, attempting to take it out with machine guns and bazookas. Some of the soldiers are killed before Iris takes to the sky and heads for Kyoto, where Ayana had been transferred earlier. The JSDF sends two F-15s in an attempt to shoot Iris down, but it is able to evade them and almost kills them. The fighter pilots are saved by the sudden arrival of Gamera, who engages Iris in a mid-air battle. The JSDF ends the battle by shooting at Gamera, which slows him down and allows Iris to continue on to Kyoto.
Soon, Iris lands in Kyoto and fights Gamera on land with Ayana watching and commanding to kill it. Iris manages to knock Gamera down for the count and then attempts again to merge with Ayana; when Moribe intervenes, the creature swats him aside and sucks her into its body against her will. While inside, Ayana realizes that she fueled Iris' destruction with her emotions - it was her hatred that led to the death of her adopted parents, and Super Gyaos instead of Gamera actually killed her parents. All seems lost until Gamera suddenly punches through Iris' armor and rips Ayana out.
Infuriated, Iris pins Gamera's hand to a wall with its spear hand and begins to absorb Gamera's energy. Its tentacles begin to form plasma balls, when Gamera quickly uses a plasma ball himself to sever his own hand. Iris fires the absorbed plasma balls at Gamera who uses his stump to turn the plasma into a plasma fist. Gamera then uses the fist to slice through Irys's chest, killing it.(exerted from Wkizilla)
Battle vs. Eva Unit 01 (by MrPacheco101)
"Unknown flying objecting heading towards Tokyo-3"
In the contrlo area of Nerv Headquaters Major Misato Kutsuragi is watching the screen with Eva Unit 01 lying face down with the Positron Sniper Rifle."Remember Shinji, once it comes down shoot it understand?" Misato said on the overcom."Understood Misato, over and out." Shinji replied back in the cockpit of the Eavangelion.
The meteor crashes into the ground and causes a huge crater to form, Unit 01 has its finger on the trigger. The meteor cracks open then Irys comes out and takes flight,letting out a bellow moan."What the hell is that!?" Shinji screams."Who cares open and commence fire!" Misato yells out. Unit 01 pulls the trigger and lops off one of Irys's tentacles, Irys moans in pain then fires its sonic beam. Unit 01 rolls out of the way, but the Positron Rifle is destroyed; Unit 01 gets up from the ground then gets hit in the left shoulder from Irys's sonic beam."Gah!" Shinji screams in pain, then Unit 01 starts sprinting with Irys's sonic beam trailing behind the Evangelion.
"Launch the Pallet Gun!" Misato ordered.
The weapon slot opens out in the ground and Unit 01 grabs the gun, then turns around and opens fire damaging Irys's left wing. Irys falls to the ground in pain with Unit 01 closing in on it."Finish it Shinji." Misato ordered, Unit 01 then prepares for the final blow."Rodger Misat--" Shinji stops at mid sentence as a strange light began to cover the cockpit."Come with me.Come with me to paradise" a soothing voice said."Oh o-okay." Shinji is attracted to light and looses control over Unit 01 and drops the Pallet Gun. Irys gets up and comes face to face with the Eva, then slowly wraps it tentacles around it and constricts.
"WHAT THE HELL IS GOING ON!" Misato yelled
"We lost communication with Shinji and Eva Unit 01 is losing power!" a Nerv worker said.
"At this rate we'll lose both Shinji and the Eva." another worker shouts out.
" Initiate the back up power then!" Misato yells out.
" We can't! Something is not letting us through Unit 01's main frame." A Nerv worker points out.
" Oh-h-h-h God." Misato gasped, realizing that she's now losing Shinji and the Eva that will no longer protect them from threats like this.
Unit 01's body is being constricted until his hand slowly began to move." Unit 01 has entered Beserk Mode!" a Nerv worker yells out." Oh no." Misato said realising what will happen. Unit 01 frees one of its arm and tears off another one of Irys's tentacles, Irys bellows in pain then throws Unit 01 far away from the injured kaiju. Unit 01 gets up and lets out a roar, then pulls out the Progressive Knife and charges at the injured kaiju; Irys fires its sonic beam and hits Unit 01 in the side of the face, but the enraged mech is still on the move and jumps up into the air.
Unit 01 comes down and plunges the knife into Irys's chest, then slices upwards killing the mighty beast. Irys falls to the ground and gasps its last breath, Unit 01 lets out a victorious roar then rips the flesh off the fallen beast and eats it.
" Unit 01 is now eating the unknown monster" A Nerv worker said in shock.
"I know. I know." Misato said solemnly watching the carnage on the screen.
" Nothing can tear a child from a mother's grip."
Winner: Eva Unit 01
Although Irys has more votes, i went against the popular vote and gave the win to Eva Unit 01 one cuz the people who voted for it gave a Good and resonable reason why Unit 01 should win than the people who voted for Irys.