Children of Saint Robert's Orphanage

In the IDW continuity, the children of St. Robert's Orphanage are a group of human orphans first appearing in Kingdom of Rats, part 2. The Invasion of the Triceratons in New York City had destroyed the orphanage, leaving the orphans homeless. The came across the ruined orphanage, and mischievously decided to use his flute to lure the orphans to one of the city's destroyed bridges, with the intention of forcing them to jump off the bridge for his amusement.

In Kingdom of Rats, part 4, the disrupt the Rat King's activities, forcing him to flee. The Turtles take the children to their estranged father, convincing him to take the orphans into the care of his.

In the Michelangelo Macro-Series issue, a disapproving Splinter privately agrees with his son to take in the children to be raised at, on condition that they be trained as future. While Leo and his brothers and  are reluctant to start another dispute during a shaky détente with their father whom they battled as an enemy during the  war,, who has had more recent disagreements with Splinter than any of the Turtles, angrily rejects turning the orphans into weapons. That night, Mikey manages to incapacitate the Foot guards and spirit the orphans out of Foot HQ and into the sewers of New York City, with the intent of bringing them to the in Northampton where he will raise and train them peacefully, just as  had done for the Hamato Children during Splinter and the Turtles' previous human lives. In reality, Mikey quickly finds that he has no idea how to look after so many children on his own. Just as the weight of the situation really begins to weigh on Mikey's mind, he and the orphans are tracked down in the sewer by Splinter, his chūnin Jennika and the other Turtles, and Splinter angrily demands the orphans' return. But a determined Mikey instead hurries to move the children deeper into the sewer and away from his father's reach. After Splinter's continued objections, Mikey faces him and furiously shouts, "Screw you!" Everyone is stunned, and Mikey goes on to denounce his father and his many broken promises, comparing him unfavorably to the. Enraged, Splinter engages in one-on-one combat with his son, and though Mikey is no match for his father, he stubbornly holds his ground. When Splinter realizes Michelangelo would truly rather die than surrender, Splinter abruptly congratulates his son Leonardo as jōnin for using his brother to demonstrate their clan's dedication at protecting the city's people. In a face-saving lie, Splinter then feigns that his prior agreement with Leonardo was actually that the orphans would be materially cared for by the Foot Clan but trained in ninjutsu by Michelangelo of Clan Hamato, then when they come of age, will only then be given the free choice of whether to join Foot Clan. As Splinter feels great shame for taking up arms against his son, Michelangelo had managed to enact positive change both in the professional relationship between clans and in the future of the orphans, ensuring himself a meaningful role in their upbringing.

In issue #89, the orphans have their first Christmas at Foot HQ. After a night of soul-searching in which Splinter is supernaturally visited by the ghost of his clan brother and three members of the, he decides to take his own role as a father and caretaker more seriously. Using Foot Ninja to forcibly summon the Turtles and to HQ, he surprises them all with a Christmas party for their family and the orphans, with himself dressed as Santa Claus for the occasion.