User blog comment:Asfidyll/Ryvar, the Nether's Guardian/@comment-24606304-20140410165429/@comment-10253076-20140410185403

No, none of the bonuses will stack WHATSOEVER. Each bonus given to a guarded ally is simply refreshed. (Otherwise even a Lux could easily gain 400 AD, 800 AP and 1200 bonus health at level 18 within a very short time haha)