WARNING: The following contains major spoilers for Teenage Mutant Ninja Turtles: The Last Ronin #1 by Kevin Eastman, Peter Laird, Tom Waltz, Esau, Isaac Escora, Ben Bishop, Samuel Plata, Luis Antonio Delgado, and Shawn Lee, on sale now.
When Teenage Mutant Ninja Turtles: The Last Ronin was announced, fans immediately started the guessing game as to who the final Ninja Turtle would be. While Leonardo or Raphael could have survived due to their strategic skills or Donatello due to his genius. However, The Last Ronin #1 reveals it's Michelangelo who's shed his comedic demeanor and is now looking to avenge his brothers by killing Shredder's grandson, Oroku Hiroto.
But given what's transpired in the years prior as the Heroes in a Half-Shell fell, this story reinforces that the Splinter Clan's biggest failure is fatherhood.
In the IDW main continuity, Splinter didn't fully realize his vision which is what the Turtles are doing now in Mutant Town with a dojo in his name. He didn't see eye to eye with them, and while they can be stubborn, so too was Splinter. It's why he and Shredd fought so many times in the past and present. Even Leo knew their master was a bit headstrong at times, and that's why a rivalry ensued when Splinter took over the Foot after Shredder died.
It always seemed a bit off that he didn't perfect his parenthood with his own sons, only to try to nail this with a group that was once killers. The Turtles knew they weren't a finished product and even when Raph wanted to believe they were, it became clear there were gaps in their upbringing that Splinter was responsible for. He does have some blame to take with Raph running away after becoming too aggressive and also, to be accountable for Leo's leadership wavering at times.
Now that he's gone, they want to get it right which is why they've adopted the mutant strays, with Mikey ironically being the lead den father. Leo's helping out as a dad too but the kids really love Mikey as he tries to bridge two eras, using what Splinter taught and what he knows is the way forward in order to evolve.
But in The Last Ronin, as we see a cyberpunk utopia where robocops are into order through an iron fist and most mutants have been eliminated, it's clear whoever officially became this future leader failed.
Given how hard he's taking things, it seems like Michelangelo ultimately repeated Splinter's mistakes, as indicated by his deeply personal anger and frustration in this issue. And it's excessive, it's not hard to see why the ninja feels like he's let down many generations before.
Protecting the future ninjas and mutants ended up being too far out of reach, so it does seem like there's only a legacy of disappointment that's been handed down with Mikey at fault for letting everything and everyone fall through the cracks. Splinter didn't protect the future properly and obviously, Mikey was doomed to repeat those mistakes and sins of old.