
It's worth noting that Oildrinker is a Chojuh, or "Super Beast," as opposed to a Kaiju. He's considered the last Chojuh ever at the time, left over from the great invasion of Chojuh that occurred in the last series, Ultraman Ace. Oildrinker being overpowered and devoured by Astromons was meant to show how much stronger Taro's kaiju were compared to Ace's Chojuh.