|First appearance||Mario Tennis Aces (2018)|
- “Bwa ha ha! Glad you could make it, Mario! Lucien and I are now one, allowing me to finally achieve absolute power!”
- —Bowcien, Mario Tennis Aces
At the start of the battle, Bowcien will summon a giant force field and five small portals. In order to dispel the force field, Mario must hit the tennis balls fired through the portals back at them; each portal takes two hits to break. Any successfully blocked Zone Shots will automatically return to and damage the portal that fired them. After a few hits, Bowcien will move the portals; a portal will also move after it takes a hit. If Mario misses the portals and hits the force field with a tennis ball, Bowcien laughs at him. When all of the portals are destroyed, the force field will disappear, and Bowcien will launch a blast of energy at Mario, which he must return four consecutive times. This will allow Mario to damage Bowcien by hitting him with a Zone Shot. Once hit, Bowcien will launch tornadoes at Mario, much like Petey Piranha, then create three shockwaves which Mario must jump over. After this, Bowcien will create another force field and five more portals, and Mario must destroy them to make him vulnerable again. Once the force field is gone, Bowcien will fire another energy blast at Mario, this time faster than before. After Mario hits Bowcien with a second Zone Shot, he will create a fiery circle in the center of the arena, then repeat his attacks from the first time he was hit. This time, he will create five shockwaves instead of three. Once Mario destroys Bowcien's portals and force field for the third time, he will shoot an even faster energy blast than before. Four consecutive returns and one more Zone Shot will destroy Lucien, ending the fight. The broken remains of Lucien will cause the temple to crumble, but Mario is teleported out before it caves in on him.
Bowcien's battle theme is a rearrangement of Bowser's battle and level themes from Super Mario 64.
Names in other languages
Shèng Défēn Kùbā
|Saint Defen Bowser|
|Dutch||Bowcius||Derived from Bowser and Lucius (the Dutch name of Lucien)|
|French||Bowseth||Derived from Bowser and Jeseth (the French name of Lucien)|
|Italian||Lucignowser||Derived from Lucigna (the Italian name of Lucien) and Bowser|
|Spanish||Bowcius||Derived from Bowser and Lucius (the Spanish name of Lucien)|
|Main||Big Dry Bowser • Black Bowser • Blockhead Bowser • Bowcien • Bowletta • Dreamy Bowser • Dry Bowser • Fury Bowser • Giant Bowser • Giga Bowser • Mega Baby Bowser • Mega Bowser • MegaDragonBowser • Meowser • Metal Bowser • Molten Bowser • Shiny RoboBowser • Shrowser|
|Other||Alarm Koopa • Black Hole Bowser • Bowser Sphinx • Bowser the Brash • Capt. Bowser • Dark Hammer Slam Bowser • Hammer Slam Bowser • Mushroom (status effect) • President Koopa • Rookie • Shroob mushroom • Tail Bowser • Wizard Bowser|