Pururu

Pururu makes a re-appearance in episode 157, where she comes down to Earth to give the Keroro Platoon checkups and stays there for a few more episodes, but her appearances are limited. Episode 162 explains how she began her career as a nurse; in a plot to retrieve back a secret base from a trio of Keronian bullies, the tadpole versions of Keroro, Giroro, Dororo, and Pururu team up, and as an ambush, Pururu was disguised as a bee and was assigned to attack the chief bully using a needle. While doing this, she enjoyed it, and when she grows up as a nurse, her weapon of choice is a large light-pink ball-point syringe similar to the needle she wielded as a child.

Her most current relationship is with Keroro, who now has an amorous crush on his childhood friend. However, she feels more sibling-like feelings to him, Giroro, and Dororo, since she sees them as childish as they were when they were tadpoles. Giroro used to have a crush on her when they were young, but now harbors stronger feelings toward Natsumi.

She became friends with Chiruyo Tsukigami, who is a member of the Newspaper Club at Fuyuki’s school, while trying to help her get closer to Fuyuki, realizing that Chiruyo had feelings for Fuyuki. Source - Wikipedia