Series: Brave of Legend Da Garn

Brave of Legend Da Garn (伝説の勇者ダ・ガーン) is a Yuusha (or Brave) series.Yuusha (or Brave, as it is often referred to) is a franchise that took place after Takara had ended the Generation One story-line of Transformers in Japan. Shortly after the end of Transformers Victory, Transformers dropped out of popularity dramatically and Takara used the formula developed in Transformers Masterforce and Victory to create a successor.
In each Brave series there is a main hero robot toy, who is usually the most or next-most expensive toy in the line, backed up by one or two support combiner teams and later receiving a combiner partner upgrading the hero to its most powerful form. (Wikipedia)
Da Garn is the third Brave series, debuting in 1992.