I know this manga likes hyperbole very much, but casting a super-tornado, and a super-tsunami, showing how it devours the earth below them and wrecks it apart -- means they just obliterated at least half the population of Earth. This is one of those moments where suspension-of-disbelief gets completely shat on.
I figure the author wanted to showcase an "epic fight", but you cannot have your cake and eat it too. If the spells were not meant to destroy the planet, do not actually show it destroying the planet for fuck's sake.
P.S: It is also way too naive to have assumed that Tartaros, and Ido to some degree, could've had a simple happy ending, as if nothing never happened.
Tartaros actually tried to kill people, and might've actually succeeded given the large scale of his assault. It is not a "teehee I guess I went a bit too far". Premeditated, large-scale homicide is not something you can go "teehee-pero" over.
One of the major faults of this story, is when it tries to tuck away shit under the rug. For the most part, it's played for gags, but this is one step way too bloody far.
Tartaros does not deserve the sympathy he's being shown here, neither any form of redemption.
P.P.S: I get that this is primarly a gag manga, but you cannot have this overblown drama arc -- and then go: "drama? I never did such thing."
If you want drama, you also need consequences. And I bet 100% that there will be absolutely none.