i wonder if this is where the idea for super tengen toppa gurren lagann came from. like ra oh and STTGL are both giants made out of a bright glowing flame and getter robo is a HUGE influence on TTGL.
I recall that in a interview with Kazuki Nakashima (screenwriter of Gurren Lagann and former assistant editor of Ken Ishikawa), said he wanted the second half of the anime to match the same energy and scale as Kyomu Senkei (Alongside Ishikawa other works).
And looking at this series, it's clear he drew those inspiration when crafting GL.
In other words, GL takes a lot of inspiration from Ishikawa works, with Getter and Kyomu being it's strongest influence.