It has to be both, at least for Island Time. You need to complete the campaign on both sides, and there are quests/vendors from faction-specific NPCs. Now is a good time to level whatever faction you need with the 20 year anniversary XP and rep buffs.
![Lp. Точка Невозврата #10 СОЕДИНЕНИЕ УСТАНОВЛЕНО... [Другой Бункер] • Майнкрафт](http://i.ytimg.com/vi/c4b5fWH-0qQ/mqdefault.jpg)
meme was spot on
so do you need to complete the achieve with an ally chara AND a horde or can it all be done with 1 faction?
It has to be both, at least for Island Time. You need to complete the campaign on both sides, and there are quests/vendors from faction-specific NPCs. Now is a good time to level whatever faction you need with the 20 year anniversary XP and rep buffs.