Lythirus is partners with Stoica of the Twelve Orders. He is a ferocious and savage Bakugan, whose style is a combination of insect and reptilian fish. Lythirus can cut anything up with his big scissor-like hands. He is usually calm, but once he gets angry, he goes on a destructive rampage. He is obsessed with winning and he will use any dirty trick to get the job done. His Battle Gear is Razoid.
Lythirus is normally calm, but he will go on a destructive rampage when angry. He is no above using any dirty tricks to win due to his obsession with winning. However, despite this, he did had some sense of honor, as seen when he call Plitheon "lower than scum" for turning his back on Jesse Glenn. He gets along with his partner Stoica, seeing how the two work together.
However, he has been proven to be insane, going as far to used the ability to drown his enemies despite the fact that he will drown his allies as well. He is loyal to the Twelve Orders, including his partner Stoica and Barodius, and Dharak as well. This shocked Lythirus when Phantom Dharak betrayed them by killing him and his partner along with Dragonoid Colossus.
He appeared again in The Sacred Orb where he aided the rest of the Twelve Orders against Neathian forces. He later fought Akwimos and even gained the upperhand against him; that is until all of the Gundalian forces were transported back to Gundalia by the Sacred Orb.
After forcefully being transported out of Neathia, Barodius has Airzel, Stoica and Kazarina lead the next fleet. In The Secret Switch, he fought in the second round during the brawl between Dan, Fabia, Jesse, and Stoica. Lythirus had Aranaut on the ropes but after Plitheon joined the fight, the two were put to shame by Aranaut's Battle Gear, Battle Crusher. Later during the third round of the brawl, both he and Plitheon managed to really make a comeback on Aranaut; that was until Hawktor joined the fight and really put the two Twelve Orders in a tight spot. Stoica, seeing that they must win the brawl to prevent the Neathians from raising the second security shield, summons his Battle Gear, Razoid, and equips it to Lythirus, giving the Twelve Orders a temporary but minor comeback into the battle. However, due to the Battle Brawlers superior brawling skills; the battle results into a loss for Gundalia.
In Curtain Call, he, along with Lumagrowl, appeared to dispose of Plitheon in result of their loss at the hands of Dan and Fabia. During the punishment, he even cunningly remarked that Plitheon was "lower than scum" for turning on his battle partner, Jesse.
In Colossus Dharak, after Kazarina announces that she has finished upgrading Exokor, the rest of the Twelve Orders attack the Neathians in order to clear the path for Dharak Colossus to destroy the second shield. For majority of the battle, he ended up fighting Akwimos for the second time while Krakix fought Coredem. The brawls continued till Dragonoid Colossus, where both he and Krakix managed to defeat their respective opponents.
He makes a later appearance in Redemption, where he and Lumagrowl battled against Sabator and Aranaut. At first, they seemed to have the upper hand until Nurzak managed to give Fabia a few pointers that she could use to her advantage against Lythirus. Stoica then activated an ability that flooded the whole entire battlefield which gave Kazarina and Stoica the victory.
In Final Strike, he and Stoica ambushed Shun and Fabia as they tried to rescue Dan and ended up battling Hawktor and Shun. The battle lasted till Dream Escape, where the it ended in a stalemate due to the Battle Brawlers escaping.
In Code Eve, he attacks and defeats Sabator in order to prevent him attacking Barodius. He later attacks Dragonoid Colossus and blinds him by shooting Acid Bubbles in his eyes so that Phantom Dharak could attack him. Dharak attacked and killed Stoica and Lythirus along with Dragonoid Colossus as it was easier to just finish them all.
- Ability Cards
- Acid Bubbles (Acid Bath)
- Megalo Thereia
- Merfolk: Subtracts 400 Gs from the opponent.
- Eel Weakness: Nullifies all of the opponent's abilities and prevents them from activating new ones, but this can only affect one Bakugan at a time.
- Megalo Skaney: Subtracts 300 Gs from the opponent.
- Death End Merman
It was revealed at the World Toy Fair 2010. The Subterra Lythirus is 630 Gs and 840 Gs. The Darkus Lythirus is 640 Gs and 800 Gs. The Haos Lythirus is 850 Gs, the Pyrus Lythirus is 800 Gs, the Ventus version is 800 Gs, the Aquos Deka Lythirus is 760 Gs and the BakuCore Aquos version is 850 Gs. He was released along with Plitheon, Linehalt, Hawktor, Contestir and Rubanoid. His Core version is slightly different from his Deka Bakugan form, because the Deka version has silver mandibles coming down from its mouth.
- He acts and talks very similar to Shadow Prove and Brontes from New Vestroia.
- Lythirus sort of looks like Terrorclaw in ball form.
- In the Japanese version, he appears to be blindly loyal to Emperor Barodius and Dharak. Even after he and Stoica are blasted into oblivion by Phantom Dharak's Chaos Magnalia along with Dragonoid Colossus, he shouts out "I won't betray you!" before dying.
- In the Japanese version, he has an alien-like voice and has a trademark laugh of "Kururururururu".
- In the anime, he is referred to as "Lythirius" despite the second 'i' not being present in his name.
- Strangely, Lythirius was released as a Deka 4 months before he was released in normal size.