Oh, that’s quite an old topic that has emerged, and I was not aware of the 10-hit limit on Hysteria. For reference: Hysterical Hysteria, Mercenaries Bwonsamdi + Leeroy Hysteria.
Besides, Rend has had some problems in interactions with certain effects, such as ‘until things die’ (e.g. King Mukla + King Krush + ‘To the Death!’) or Infernal Combustion — he would continue to shield his neighbours, despite going into negative health, and the interactions would go on until a hard cap would be hit.