One of the nice things about the Alien Hunters book is that there is no such book for 3rd-5th edition, so it doesn't make sense to do it as a supplement. Instead, I'm writing it as a short Codex, which gives me a lot of practice for other factions that simply don't have books in the period (Inquisition happens also to be my favourite faction).

This has been a nice chance to do a bit of art, which is always useful to have for future projects. Part of the book I wanted to do as a nod to the Tome of Ectoclades - a piece of wargear for the Deathwatch which would be fun to write extracts from.

What's really fun about the 35k setting is that this is when the Genestealers are discovered. The Tyranids don't exist yet, since they get their name from the planet Tyran. There are two main discoveries (if you don't include the Catachan Devil, who the Ordo Xenos haven't worked out is just a Tyranid): Tiamat and Ymgarl. Given these creatures would be top secret, I've gone with the name Tiamatii, with the Ordo Xenos noting the Ymgarl Genestealer as likely related (also some mutant uprisings that begin to appear happen to have a suspicious interest in these creatures). 

My view is that when the Tyranids attack full-scale, the name Tyranid makes more sense to adopt since it avoids the possibility of many people looking too deeply into the Ordo Xenos' interest in the Tiamatii.

I have a few Xeno creatures to do for those paegs, but have found this part pretty fun.

Art from the Xenobestiary