In three ways, he's like Rob, Mal, Den, Seb, etc. (3)
I believe the answer is:
wes
'he's like rob mal den seb etc' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'in three ways' is the wordplay.
'three ways' can mean three substitutions for 'way'.
'in' indicates putting letters inside.
'way' becomes 'w' (Compass direction - West).
'way' becomes 's' (Compass direction - South).
'way' becomes 'e' (Compass direction - East).
'w'+'s'='ws'
'ws' enclosing 'e' is 'WES'.
Can you help me to learn more?
(Another definition for wes that I've seen is " -- Anderson (film director)".)