Incidentally, re my query about Asim upthread, I also asked on RPGnet and we had a couple of other thoughts:
- Maybe Drinax unleashed bioweapons/WMDs on the ihatei on Asim in 884-5 (maybe also on the other worlds in the chain). This provoked the Ahroay'if to intervene in force (and gives extra motivation for their use of bioweapons on Drinax). By now (in 1105) the bioweapons are believed to have degraded, and/or Aslan scientists have developed cures/countermeasures. (The bioweapon in Shadows of Sindal would be a newly developed variant that the Aslan don't have an immediate countermeasure for.)
- The Solomani Confederation formed in 871. That's a fair way away, but it could have been a factor in Aslan politics at the time. E.g. maybe some Tlaukhu clans were thinking about a possible war with the new Confederation, and if that went down they didn't want to also be fighting the Imperium, so they urged the Ya'soisthea clans to throttle back coreward expansion. This consideration could be part of why the Ahroay'if settled for smashing the Kingdom of Drinax into bits instead of conquering it.
- Maybe Asim is just too brown for Aslan to want to stick around.