So originality this was going to be a Skirnir Magus who was a "Paladin" with the false focus feat. I wanted him to be an anti-magic/mage character since his backstory revolved around him wanting to kill a level 19 wizard.
Problem, the GM has gutted my backstory idea and may have made him into the "chosen one" type deal. SOOOO, I need to build a badass anti-magic MONSTER. We are starting at level 1 and leveling up FAST so I need a full levels 1-15 plan. His stats are as follows.
Str 16, Con, 15, Dex, 11, Int, 18 Wiz, 15, Cha, 11
Human, starting gold 200
Ideas?
Somewhere along the line you should pick up the Familiar magus arcana, so that once you can afford to you can get a lesser metamagic rod of Familiar Spell. This allows you to give your familiar a few castings of dispel magic at the start of each day, so it can then spend every combat readying actions to counterspell enemy spellcasters at your full caster level with no action cost for you.
Don't forget to pump Spellcraft because you can't counter a spell, even with Dispel Magic, if you can't identify it properly. Your familiar uses your ranks.
This would take a discussion with your GM, but what a Bladebound Magus, with a black blade focused on evil wizards, could easily tie in with "chosen one" archetype.
Other Class alternatives to consider
Fighter with the Disruptive and Spell Breaker Feat chain (Gear up with anti Magic Items) To my mind the easiest
Barbarian with Superstitious Rage, Eater of Magic Rage Power, Disruptive Rage, Spell Breaker Rage, Witch Hunter, Spell Sunder. This wouldn't work so much as a "Paladin," but could be a fun story with a kid who saw a mage destroy his village and pledges to destroy him. Fun for character though to my mind Superstitious as a rage power is a bear to play with.
Inquisitor with the Magic Domain, you get dispelling touch and dispel Magic as domain spells. Judgement and Banes can be used to wreck a single enemy and Inquisitors aren't seen that often.
Slayer (there is even the Church centered Deliverer archetype to make it more Paladin like)
Mesmerist with the Sapped Magic Bold Stare and Spell Anticipation Masterful Tricks.
Also with it's area dispel magic ability if this person is culturally a Paladin, will your GM allow you to wield a Holy Avenger and count as one. I can't even say that I would, but it is good to ask.
Also I forgot there is a Witch Hunter Archetype for Inquisitors
A warpriest using Improved Vital Strike to disrupt spellcasting?
would Vindictive Bastard meet you Paladin but not-a-Paladin needs?