A Seed of Light is a Consumable item introduced in Destiny 2: Forsaken as a means to unlock a new upgrade path of subclasses. A total of three Seeds of Light can be collected across different activities.
First Seed of Light
The First Seed of Light can be obtained during the events of the Forsaken campaign. Ikora Rey tells Guardians to keep their eyes upon for new journeys in the Light. Defeating enemies along the Tangled Shore will result in Visions of Light. These collectible items must be collected to complete the Visions of Light Milestone.
Second Seed of Light
After gaining access to the Dreaming City, players will need to complete a Tier 4 Blind Well event to earn another Seed of Light. This activity requires a Charge of Light – Tier II in initiate. To reach the Blind Well, start at the Dreaming City spawn point, head right and into the large structure carved into the side of the mountain. Continue through the halls until you reach the Blind Well.
Third Seed of Light
One method to obtain the third Seed of Light is to defeat Kalli, the Corrupted, the first raid boss in the Last Wish raid. The second way of obtaining the third Seed of Light is presenting an Offering to the Oracle Engine. After talking with the Queen, she will grant you a Seed of Light. Bungie has confirmed other methods to obtain Seeds of Light will be available in the future.