Kidou Senshi Gundam AGE

Both protagonists have faced tragedy. On Mars, Akito faced the death of his parents as a kid, and later as a teenager, he sees a young girl die in front of him when the colony he stays in is destroyed, he suffers from a form of PTSD due to this, he doesn't like to fight despite being good at it, he only wants to be a cook. Flit's own colony was destroyed when he was very young. Unlike Akito, he isn't afraid to fight as doing something mobile-suit related, be it engineering or piloting is the family business. Akito has Gai Daigoji as an enthusiastic older-brother figure. Flit's son, Asemu Asuno views ace pilot Woolf Enneaclesimilarly. Despite not wanting to fight, Akito is fueled with a deep hatred for the Jovian lizards because of his experiences, Flit feels a similar strong hatred towards the Vagan. That being said, Akito's motivation to fight is lowered after he learns the true nature of the Jovian lizards, in a huge contrast, Flit is still willing to commit genocide and actively denies what the Vagan are. Akito has Captain Yurika (who is his childhood friend) chasing after him, he does not like this (at least initially), whereas Flit and his childhood friend Emily do have a mutual affection for eachother.  read more 

Kio Arc is partially Part 4 as a new antagonist Ezelcant takes on the mantle of Yoshikage Kira while the others return. 

Age's 1st & 2nd arcs are reminiscent to that of JoJo's first two parts. Age & JoJo creates a span of story taking from one ancestor to their descendants including the prolonging of their arch nemesis. Flit-Jonathan Asemu and Kio-Joseph Desil-Dio Zeheart-Kars 

AGE Kio Arc is one to Stardust Crusader as the finale of the villains with the older protagonists supporting them. Kio-Jotaro Asemu-Joseph 

A must have device for your unlimited ambitions. One is for conquer the world. The other is for rule the universe. 

Both series have very similar starting points, with the cast being forced to leave their home after it's overwhelmingly attacked by an alien force. Despite having young casts and kiddier art styles, both of these shows tell serious war stories 

Both series are Mecha based Anime where there are 2 factions going to war. One Faction based in Mars who felt like they were abandoned by the Home Land earth and wish to take it back. The other Faction being based on earth and being attacked with superior technology. The similarities between the 2 shows are too uncanny at first I didn't believe it. However if you like Aldnoah.Zero you will Love Gundam Age. Enjoy!. 

Arguably the black sheep of their franchises with the poor execution and timing only to be followed up by their successors IBO and Arc V. The story pulls off a Madoka stunt but as it gradually rolls by so does the tone of the story getting intense from the light hearted looks introduced. Only difference is Zexal is for teens and AGE is for teens to adults. It was the worst time for both franchise until the sequel hits. Unlike Zexal, AGE focuses on three different protagonists and tends to be the proper remake of UC's og trilogy while Zexal repeats the trends of the previous three series but in a different and unique trend. They are not bad, it is just the timing and planning that ruined both series. Regardless the franchise did whatever it took to bring something new to the franchise for the first time in history. read more 

There's the obvious "beautifully illustrated space mech fighting against an initially vague enemy" factor, but I find them to also be similar in spirit. Gundam AGE's AGE System that learns from the Gundams' battles is similar in spirit to Gurren Lagann's Spiral Energy; just as Spiral Energy reflects how humanity keeps going and is evolving day by day, the AGE system is a weapon system that evolves right alongside its pilots. 

Similar story and mecha action. Young pilots must work together and defeat the "aliens." The aliens are advance species who are above all humankind. Wulgaru=Vegans  

Both revolve around a story where humans from mars come to invade the humans of Earth to take the planets from them, and the humans from Mars have the better technology. 

In Gundam AGE: Children must use their Gundams to save the world. In Gundam Build Fighter or GunPla, they must use their custom built plastic model to battle other players. Familiar Gundam models can be seen in both series. Both are produced by Sunrise who are known for their Gundam franchise.  

Gundam AGE is just like NGE, but much better. The mechas are better and it doesn't run out of money at the end. The protagonist knows what he must do to save the world. 

Both series attempt to make you sympathize with very obviously evil villains. 

Although the two are not related, but there's a reason why I recommend this one: 1. The character design reminds us with the character design we see before (PMMM with Hidamari Sketch, Gundam AGE with Inazuma Eleven). 2. At first glance the story is lighthearted, but the longer storyline, the more serious gradually. 

If you flipped the perspectives in AGE (focusing on the natives of Mars instead of the Earth Federation), made the story a "Band of brothers fighting for independence" style story instead of a "young boy discovers the horrors of war" style story and got rid of all of AGE's flaws, you'd pretty much have IBO.