Got my own thread asking the same question, but the more the merrier. Definitely need an answer on this, as it hugely affects the champ's usability.

Guess I need to look closer at his kit, I have no clue what you guys are talking about... lol.  Waiting til Friday to claim and build.

His passive is treated as an attack, and therefore can proc stun and warmaster/giantslayer. Also, rather than the champ being attacked needing those, it's brogni himself - so putting him in a stun/sleep/poison/etc... set, along with warmaster/giantslayer, allows him to contribute way more than you'd expect

hmm, sounds like waiting to gear and do masteries would be a wise decision until this is verified to remain