Keroro Gunsou

Meet the Sergeant!

Sergeant Keroro is a frog-like alien from the planet Keron sent to invade planet Earth (or Pekopon, as his race calls it). He is instead kept as a pet and forced to do chores for the Hinata family, which consists of paranormal maniac Fuyuki, his ill-tempered older sister Natsumi, and their manga-editing mother Aki. Keroro is given his own room in the basement of the Hinata family house, which he refurnishes and uses as a base, not realizing that the room is haunted by a ghost. In a prequel to the first segment, the Hinata family first discovers and captures Sgt. Keroro while he is scouting inside their house. Fuyuki takes the Keroball (Keroro's weapon) and fiddles around with it, accidentally sending a signal to the Keronian invasion fleet alerting them of Keroro's capture. The fleet abandons Keroro instead of rescuing him, leaving him to perform chores around the Hinata family household. (Source: Wikipedia)

Keroro: Fuse, Keroro Robot, Sir! / Keroro: Invasion! Cherry Blossom Forefront, Sir!

Pururu: Leave It to the Chief Nurse, Sir! / Natsumi: Today's Horoscope, Sir!

Giroro: The Most Dangerous Man in the Universe, Sir! / Keroro: An Occasionally Dangerous Man, Sir!

"Giroro: The Most Dangerous Man in the Universe, Sir!": Giroro is disgusted by Keroro and Tamama's lack of progress in the invasion and decides to set traps for the Hinatas using all the information he had gathered on them. He immobilizes both Keroro and Fuyuki, but Natsumi easily overcomes the traps with her brute strength and knocks out Giroro. "Keroro: An Occasionally Dangerous Man, Sir!": Giroro suspects that the reason behind Keroro's lost interest in the Pekoponian invasion comes from a difference in humidity between Earth and Keron. He and Tamama install humidifiers in Keroro's room, which drastically increases his intelligence and strength, but the room becomes overly humid when it begins to rain, causing Keroro to go berserk. The humidity attracts a Nyororo, a natural enemy of the Keronians, which feeds on all the moisture Keroro had absorbed and returns him to normal. (Source: Wikipedia)

Keroro: Heated Card Battles, Sir! / Keroro: The Targeted Platoon, Sir!

Momoka: The Best Mother's Day, Sir!

Putata & Mekeke: Hissatsu Oshigotonin, Sir!

Chibi Kero: Joriri of Back Then, Sir!

Natsumi: Goodbye, Saburo, Sir! / Fuyuki & Alisa: Monster in the Rain, Sir!

Keroro: Nyororo Extinction, Sir? / Lavie's Going to Get Married, Sir!

Kululu: Acting Commander, Sir! / Koyuki: Normal Extra-hard Training, Sir!

Keroro: Smash, Wettle Robot, Sir! / Keroro: Charge, Wettle Human, Sir!

556: How To Make Cup Ramen, Sir! / Keroro: Complete the Crossword, Sir!

Keroro: Grand Invasion, For A Limited Time Only, Sir! / Momoka, A Tanabata Exclusive, Sir!

Urere: King of Trains, Sir! / Giroro: The Beautiful Girl and the Liquid Keronian, Sir!

Fuyuki & Keroro: Unveil the Seven Mysteries, Sir! / Pururu & Chiruyo: Secret Friends, Sir!

Tamama: Rebel Without a Cause, Sir! / Kululu: Home Alone, Sir?

Alisa & Fuyuki: UMA vs. Dangal, Sir!

Keroro: Yamato and Capu, Sire!

Keroro: He'll Comb Straight Out, Singing With an Afro, Sir! / Dororo's Mysterious Mountain, Sir!

Keroro: Dive Into the Plastic Pool, Sir! / Fuyuki & Natsumi: A New Morning Has Come, Sir!

Chibi-Kero: Farewell, Summer Vacation, Sir!

Dokuku: Gas Keronian #1, Sir! / Keroro: The Top Gundam Man On Pekopon, Sir!

Momoka: Ghost: Phantom of the Hinata House, Sir!