Like their modern day counterparts, the Delightful Children From Down The Lane, they frequently celebrated their birthday and prepared a delicious cake they refused to share with anyone else. The cake's recipe was kept by their mother, who is Father's great-grandmother. When the KND attacked the Alamode to get the recipe, Numbuh 19th Century set off a defense mechanism, which caused a nuclear explosion of ice cream that froze close to five thousand operatives (all of whom had to be decommissioned after being thawed, as they were technically over 13).
- Unnamed mother
- Grandfather (Son or Nephew)
- Monty Uno (Grandson)
- Father (Grandson)
- Mrs. Uno (Granddaughter-in-law)
- Nigel Uno a.k.a. Numbuh 1 (Great-Grandson)
- DCFDTL (Adoptive Great-Grandchildren)
- The triplets' design seem to be based on the twins from The Shining.
- It's possible that one of them is Grandfather's mother. If this is the case, it may mean that one triplet can act on her own accord, meaning they may not be one entity like their later descendants.
- However, the DCFDTL are shown to be able to separate on rare occasions.
- Since their bloodline had produced Father in the current time, it's reasonable to assume that the triplets (and possibly their mother) were able to escape before the flash-freeze.
- Their mother is colored black and red, which would mean she possibly had thermal-based abilities similar to Grandfather and Father.
- In a fan interview with Mr. Warburton, it's revealed that they are, in fact, delightfulized.
- In the book 2x4 Technology Handbook, Numbuh 2 calls Numbuh 19th century a Victorian operative. It's likely that the triplets are well. Since Operation: C.A.K.E.D.- F.I.V.E said early 19th century, it's possible that they were active at the earliest in the late 1830s to the early 1840s.
- When you look at the recipe imprinted on Numbuh 19th Century's chest it says Grandma's Recipe. Since the recipe is the triplets mother's it's likely that it is her grandmother's recipe.