When first encountered, he will be crying as all the Grubs have been taken from their dens. When the Knight returns after freeing Grubs, the Grubfather will reward the Knight with Geo and other items according to how many Grubs have been saved.
After all Grubs have been rescued and rewards collected, returning to the Grubfather will reveal that all the Grubs are gone from their holes, and the Grubfather is now laying in the centre of the room, his stomach extremely bloated. The muffled noises of Grub chatter can be heard from inside of him.
Grubs are creatures found trapped in glass jars throughout Hallownest. When The Knight is close enough to their location, a faint crying noise can be heard in their general direction. They talk in high-pitched babbles and cannot be spoken to. When hit with the Dream Nail, their thoughts read "...Home...". They can be freed by breaking the jar with the Nail, after which the Grub will burrow into the ground and return to the Grubfather. Obtaining the Collector's Map after beating The Collector shows the locations of unfreed Grubs.
|Rewards are based on the total number of grubs saved, not which grubs have been saved.|
|3||Forgotten Crossroads||Breakable wall||30|
|4||Forgotten Crossroads||Spike bounce||40|
|5||Forgotten Crossroads||Mothwing Cloak (or nail bounce)||Mask Shard|
|8||Greenpath||Defeat Moss Knight||70|
|10||Fungal Wastes||Mothwing Cloak||Grubsong|
|11||Fungal Wastes||Mantis Claw||90|
|12||City of Tears||-||100|
|13||City of Tears||-||110|
|14||City of Tears||Desolate Dive||120|
|15||City of Tears||-||120|
|16||City of Tears||Monarch Wings||Rancid Egg|
|17||Crystal Peak||Mothwing Cloak
and Mantis Claw
|18||Crystal Peak||Crystal Heart||150|
|19||Crystal Peak||Monarch Wings||160|
|20||Crystal Peak||Crystal Heart||165|
|21||Crystal Peak||Mothwing Cloak||170|
|23||Crystal Peak||Platforming||Hallownest Seal|
|24||Resting Grounds||Desolate Dive||200|
|26||Royal Waterways||Crystal Heart
or Isma's Tear
|27||Royal Waterways||Isma's Tear||210|
|28||Howling Cliffs||Mantis Claw||215|
|29||Kingdom's Edge||Desolate Dive||220|
|30||Kingdom's Edge||Mantis Claw||220|
|31||Fog Canyon||Crystal Heart||Pale Ore|
|34||Queen's Gardens||Mantis Claw||240|
|40||Ancient Basin||Mothwing Cloak
and Monarch Wings
|41||Ancient Basin||Desolate Dive||270|
|42||The Hive||Desolate Dive
& Isma's Tear
|43||The Hive||Desolate Dive,
Isma's Tear &
|44||Tower of Love||Love Key||295|
|45||Tower of Love||Love Key||300|
|46||Tower of Love||Love Key|
|Dream Nail Dialogue|
- Occasionally the Knight will come across a Grub Mimic trapped in a glass jar that will transform and become hostile when freed. The easiest way to check is to Dream Nail them. Grubs will always say "...Home..." but Grub Mimics will say "...Kill...", "...Empty... " or "...Other...".
- Upon receiving the final reward(s) from the Grubfather, if the Knight rests at a bench and returns, the Grubfather will have swallowed all of the Grubs and is lying engorged on the floor. The Grubs' babbling can still be heard from inside him, indicating they are alive.
- It is unknown whether this is a cruel act on the Grubfather's part or just a part of Grub biology. The achievement earned after turning in all Grubs is called "Metamorphosis," and the charm references a "Grubberfly" - this may imply that the Grubs have entered a larval stage for a butterfly-like creature with the Grubfather acting like a cocoon.