The Season of Blood offers a new event called Blood Harvest, which is similar in a way to the Helltide Event, causing an area to be swarming with vampires.
Throughout the affected areas, you will be able to find Seekers Caches, which can be unlocked to obtain various rewards related to the season and this event.
To unlock a Seekers Cache, you will first need to find a Seeker Key, which can be done in an area affected by Blood Harvest.
How To Get Seeker Keys?
Seeker Keys are obtained from Blood Seekers, which are stronger variants of enemies that have a good chance to drop the keys when they are slain.
Sometimes you will be able to run into Blood Seekers but the only guaranteed way to get them to spawn is to interact with Sanguine Altars.
Activating Sanguine Altars will require that you have 15 Blood Lures, which drop from enemies that you defeat in the Blood Harvest zones.
How To Use Seeker Key?
Once you get your hands on a Seeker Key, you will be able to use it once you interact with a Seekers Cache and this will drop loot related to the season.
You can hold multiple Seeker Keys in your inventory and even if the Blood Harvest zone moves, you will still have the same amount of Blood Lures and Seeker Keys.
It is best to gather as much as you can and use them right away whenever you find a Seeker Cache as these are plentiful in Blood Harvest zones.
Seeker Cache Rewards
Once you open a Seeker Cache, you will get certain rewards that include items, whose quality varies based on your level that also has a chance to be Legendary.
Amongst the other rewards, you will be able to obtain different Pacts (Ferocity, Divinity, or Eternity) that can be used to alter the Pacts that a piece of armor has.
Additionally, you will be able to get Potent Blood for upgrading or unlocking Vampire Powers and Blood Lures to help you continue the cycle of farming Seeker Caches.
Open Seeker Caches is one of the best ways to get good loot during The Season of Blood as you can continuously do this and level up at the same time.
All you need to do is rinse and repeat when it comes to collecting Blood Lures, obtaining Seeker Keys, and opening the Seekers Caches.
One of the best things about a Blood Harvest is that you do not lose the Blood Lures or Seeker Keys, which allows you to simply pack up and move to the next affected area.