Transformers vs Marvel
Connection:
Both are planetary conquering rulers that were originally born into oppression as a mistreated lower class, where their innate talent was disregarded and suffered constant abuse at the hands of their superiors to the point both lead a revolution against their oppressors, with their charisma and power luring others who felt discriminated to their side and forming an organization (Decepticons and Brotherhood of Evil Mutants respectively)
Both had a friend that originally sided with their views (Optimus Prime and Charles Xavier/Professor respectively), but sided against them in a long war as both friends were torn apart as they grew more violent, even forming their own teams to combat their (Autobots and X-Men respectively). This violent progression made them more and more corrupt and ruthless as time passed, almost losing sight of what their original and noble aims were
Both ultimately saw that their wars was doing more harm than good and abandoned their evil ways, joining up with the opposing side for the betterment of their entire species as a whole while struggling against their past misdeeds and kill count