Capitalizing on an ally's fear effects

[thefifeman]

Under level 10, what feats can I, an Avenger type sword-and-board Vigilante, take to capitalize on my ally's constant fear effects? I'm already running Variant Multiclassing for the Cavalier Order of the Asp Challenge effect. Beyond that I'm having trouble finding feats that give you a bonus against Shaken and Frightened enemies.

[Axel_Neco]

Well, there's always the classic Shatter Defenses trick. All it cares is that you hit an opponent in a state of fear. Hit once, treat as flat footed until end of next turn... so you hit them again at the start of next and keep the cycle of pain going. All you need is Weapon Focus with your weapon of choice, and Dazzling Display. Works good on rogues, but works wonders when the party is built around fear tactics.

[Petrukio]

Well, there's always the classic Shatter Defenses trick. All it cares is that you hit an opponent in a state of fear. Hit once, treat as flat footed until end of next turn... so you hit them again at the start of next and keep the cycle of pain going. All you need is Weapon Focus with your weapon of choice, and Dazzling Display. Works good on rogues, but works wonders when the party is built around fear tactics.

Combine that with Shadows of Fear (https://www.d20pfsrd.com/feats/combat-feats/shadows-of-fear-combat/) from Ultimate Intrigue if you're playing a rogue or or stalker vigilante of 3rd-level (or higher), or otherwise have access to Hidden Strike or Sneak Attack - the first time each round that you hit a creature suffering from a fear effect, you can deal hidden strike or sneak attack damage as if you were flanking that creature.