You can catch it after the battle. I can show the locations for all of them in the comments if anyone wants

Are the former titans stronger than usual?

Not really. But a few have their hidden abilities

So it doesn’t matter too much that I defeated the titan Klawf?

Klawf only has anger shell, so if you caught it, all you would get is the former titan mark

I defeated it thinking I would get sweet herba mystica because that was the only one I was (and still am) missing

sweet or spicy code