How do you get that squid guy ?

Story banner

As Nanophobia mentioned, story banner. As a Story Lock, they have a chance to show up there, or in rate up banners. It has been a few years since the last Rate Up banner, but he does show up in a banner later this year.

https://fategrandorder.fandom.com/wiki/Singularity_Repair_Support_Campaign#Summoning_Campaign_1

If u want 3☆ or any servant that's story locked

Your best chances are either

Rate up banner or story banner

The more ahead in the game you are the larger the servant pool in story banner becomes

Gotcha, this time i would ready to at least getting every low star servant limited and story locked for sure.

Actually, the class based banner is the best banner to get those servants.

That is really just another rate up, but hasn't been seen for a few years

Which is why I forgot about it

A shame you forgot it, just like the developer.

I'm just glad I managed Sitonai (on both accounts, even) and Hessian Lobo (on the alt) during the last Extra Class banner. Shame I didn't get Gorgon.

I'd love to see more. Even if they were a surprise bait banner.