X Saber Airbellum Discard Issue

Suppose my opponent attacks me with airbellum he(Or in RL at random) selects gorz,and i chain the effect to summmon gorz to the field,will i still have to discard?

Lets say you attack your opponent directly with Airbellum while he has no cards on the field. Airbellum's effect will activate at the same time as Gorz. Since you are turn player, your effect will be placed as chain link 1, and Gorz as chain link 2.

Chain Link 1 - Airbellum
Chain Link 2 - Gorz

Resolves backwards

Gorz is summoned
A random card is discarded.

So Gorz will be summoned before you randomly discard.

Airbellum's effect does not target a card in the hand. It hits a RANDOM card. In KCVDS, this is often done by the opp selecting a card, but that the truth is it is meant to be RANDOM. There is no target so a random card is discarded when his effect RESOLVES. If you have Gorz in hand, you can chain it to Airbellum's effect in which case he will summon himself and a token, then Airbellum will randomly discard 1 card from the hand.