L is Flashy Flash? That's news to me
There are references, yeah, but I think you're reading too much into things considering it's just one of 50ish quests.
Most people notice the One Punch Man parallels, sure, but does anyone notice the DOTA parallels? ZAP is more like Tinker than Child Emperor, Sword Saint Juggernaut is a fusion of Spamtom from Deltarune, Gilgamesh from Final Fantasy and Phantom Assassin from DOTA 2. Swiftstroke is wearing d-os' alternative outfit from One Punch Man. Slime God's design silhouette is based on Sou from Monster Musume. Furnace Knight is based on the Smelter Demon from Dark Souls 2.
Sure, you may recognize some aspects of the characters that parallel to other pieces of media, but there's often lot more to most of these things that are easily missed. I think you might be able to find a reference or influence in
every single character if you try hard enough. The quest and weapon names are also absolutely full of references.