Please help with a Caster build

[relytdan]

I am looking more for a sustained offensive caster like Psion , Sorcerer,
then also is there any spell that will make the character invisable to blindsight or other similar effects

[Xervous]

Your definition is too broad. Do you want the character to use direct damage effects or crowd control tactics?

As for foiling blindsight and similar, a good enough hide check paired with the feat Darkstalker will allow you to avoid detection.