Any League that captures a Beacon must defend it from increasingly powerful waves of Balur's Black Horde. Defeating them will earn you Dark Essence, which your League may use to "Darken" your own Units - reducing their need for food, increasing their strength, and improving their effectiveness in combat.
Dark Essence collected by your League is stored inside your League’s Beacons. League Marshals and those they authorize are allowed to transfer Dark Essence between the League’s Beacons, should they hold more than one.
A Beacon must be at least Level 2 for you to start using Dark Essence. Level 2 Beacons allow you to darken Infantry Units, Level 3 Beacons allow you to darken Infantry and Cavalry Units, and Level 4 Beacons allow you to darken Infantry, Cavalry, and Occult Units. Level 5 Beacons allow you to darken all types of Units.
Your personal access to Dark Essence is defined by your League Rank and the privileges set by your League Marshal. If you are a League Marshal, you can give other League Members access to Dark Essence in the following way:
1. Go to the "My League" tab at the League Hall and open the list of League Members.
2. Tap on any League Member's Rank icon; you will then see a full list of Ranks.
3. Press the arrow next to any list item to review and manage the Privileges granted to Members who are of this Rank.
4. Check the "Dark Essence Access" in the list of Privileges and tap the “Apply” button below.