Who should read/play it
Mark of the Xenos is a supplement for the Deathwatch RPG (by Fantasy Flight Games). While the Deathwatch Core Rulebook provides the rules for playing as Space Marines, it only scratches the surface of the enemies they face. This book serves as a definitive bestiary and lore compendium for the Game Master (GM). It provides the statistics, special rules, and background lore needed to run battles against the major alien races of the Jericho Reach. Warhammer 40K - Deathwatch - Mark Of The Xenos.pdf
Don't just drop the stat block on the table. Use the book’s "Deathwatch Intelligence" style. Before the mission, give the players snippets of data from the PDF. Who should read/play it Mark of the Xenos
: Engage with the lore provided. The Deathwatch series offers a rich narrative that can add depth to your gaming experience. Integrating your characters and actions into the lore can make the campaign more immersive. It provides the statistics, special rules, and background
The specialist rules for Kill Team: Cassius and the subsequent Deathwatch Kill Teams borrow heavily from the formations listed here. Understanding the original source material gives you an edge in customizing your operatives.