Increasing DC on Spells

[Barbarian Horde]

Grease I shall use as an example. Can you add you main modifier to the difficulty to save?

I don't think you can.

So could you use feats to increase the DC instead? Moving the dc 10 to stand to a 12 or 16 using feats such as non violence and spell focus conjuration and great spell focus?

[Curmudgeon]

The formula is always the same: Spell DC = 10 + spell level + spellcasting ability bonus. You can change the spell level with Heighten Spell, and you can boost your casting ability as high as the rules allow.

[Barbarian Horde]

A creature can walk within or through the area of grease at half normal speed with a DC 10 Balance check.

Okay now maybe what Im asking wasn't specific the first time.
The feats I listed above or any that you can think of would it increase the DC on the balance check.

Or vertigo the spell, it has the same pre established balance check.

[Barbarian Horde]

One of the first lines from vow of nonviolence
The saving throw DC for spells you cast or other special abilities you use against humanoid or monstrous humanoid targets is increased by +4

[Curmudgeon]

You're confusing your terms. A skill check is not a save. If a skill check has a stated DC, the DM can add situational modifiers, usually +/- 2. For example, the DM might increase the Balance check DC if the surface was coated with ice before Grease was cast.

[atemu1234]

A creature can walk within or through the area of grease at half normal speed with a DC 10 Balance check.

Okay now maybe what Im asking wasn't specific the first time.
The feats I listed above or any that you can think of would it increase the DC on the balance check.

Or vertigo the spell, it has the same pre established balance check.

Nope. It takes researching new spells to increase the DC. It wouldn't be too hard, I would think.