The description of the item says "one-handed", which I thought would work great for a Sword Saint and look cool. Now I see that it occupies both weapon slots, and I can't seem to make Spell Combat work with it. (Screenshot attached).

Is two-handed wielding something you can toggle for the character?

can you equip a shield in the other hand?

Equipping a shield removes the weapon. So I guess the description of the sword is wrong?

Two bladed sword is supposed to be a 2handed weapon, as it is basically a blade staff.
Good news is that the savegame editor is coming along nicely, but it is probably a month or more away from being able to alter feats.

Stats look the same as some 1-handed weapons, so what is the advantage?

Not sure there is one, aside from strengh bonus calculation.
There are several 2 handed weapons with the same damage and crit range as a 1 hander.

You get to make a 2nd attack with it, it's just like 2-weapon fighting (at least, that's how it works in PnP).

I think it qualifies as both Functionally i is Two one handed weapons attaches you trade more damage for less accuracy
(at least that how it worked in D&D) Not fammiliar with Pathfinder

It also means you need to spread your stats more It's a matter of taste and style really

Devs have stated clearly magus casting abilities will NOT work with two handed weapons