We need strategy guides for this.

What part are you talking about? I don't remember anything in G19 mentioning dual swords, etc.

If you're talking about the various forms of Gilgamesh (most know him as Girgashiy), most forms simply drain your health, so you need to have health pots, demi-god, or some other way to recover it back. The other big move is Soul Absorption, and when he starts using that, you want to stay away from him and hit the shadows that appear until the boss falls.

I know, I just meant some legit strategies for other players.

I beat Girgashiy perfect form with a faulty plan that probably wouldn't work for others.

It's just there isn't much info for this on the wiki.

When you say "perfect form" are you referring to the one in Realization? I just updated the strategy for that one.

The way I did it was to die until he's at 25% hp where he will begin using soul absorption, then summon a pet, have said pet attack him while you spam the shadow that is summoned. Repeat the pet spam each time he uses soul absorption and eventually you'll kill him.