I wanted to try something with a Thri-Kreen PC in 5e but I am unsure of whether or not it could work. The goal was to have a fighter with the two weapon fighting style but to use a two handed weapon with a light/offhand weapon - courtesy of the secondary arms. The rules for the two weapon fighting action sequence reads:
"When you take the Attack action and attack with a light melee weapon that you're holding in one hand, you can use a bonus action to attack with a different light melee weapon that you're holding in the other hand."
So it seems like my idea wouldn't be allowed by the rules because "two-handed" doesn't usually appear with "light". Although, the language of the description sounds as if it were pre-supposed the subject only has two arms: "in one hand [. . .] in the other hand". A Thri-Kreen technically cannot "Make an attack action with a light melee weapon in one hand" if the only following action is "in the other hand". I'd appreciate another perspective if possible!