Kousoku Denjin Albegus (TV Series, 45 episodes, AniDB)

Requested on Oct. 25, 2019, 9:35 p.m.

The Gerinya empire attacks the Earth after hundreds of years of peace. The last hope seems to be Dr. Mizuki`s latest creation, the trio of Arbegas robots, able to combien and form one might metal giant. The pilots are Dr. Mizuki`s genius daughter Hotaru, cheerful martial artist Daisaku Enjouji, and aloof tough guy Tetsuya Jin... Source: ANN