[HnT] Thunder Mask - 01 (English Subbed) 

This is the Kaiju series known in English as Thunder Mask. It's not very well known, so much so that it doesn't even have a Wikipedia page. It's quite notable though for the fact that it's a partially lost series. Rumor has it that the original prints for the series were destroyed which is a shame. However, a few episodes survive, in horrifically low quality, and were subbed by the awesome Hi no Tori Fansubs, go check them out and throw them some love.
www.hinotori-fansubs.com/