I did my best on tagging this. Here's some important contexts for the piece that are spread throughout the artist's content:

-This artist portrays Android 13 as being one of Dr. Gero's sons. The version of him here is meant to be him pre android.
-The boy with curly hair is meant to be Dr. Hedo's father. He has no official name, so I had his tag just be "Hedo's Father".

Hedo's dad look like a slime down Kazuma Kuwabara from Yu yu Hakusho.

ElfinElixir said in comment #2448155:

I did my best on tagging this. Here's some important contexts for the piece that are spread throughout the artist's content:

-This artist portrays Android 13 as being one of Dr. Gero's sons. The version of him here is meant to be him pre android.
-The boy with curly hair is meant to be Dr. Hedo's father. He has no official name, so I had his tag just be "Hedo's Father".

Interesting enough I seen one presents Android 13 as a younger Dr gero