Mazinger

Mazinger (マジンガー, Majingā^?) is a long-running series of manga and anime featuring giant robots or mecha.

The series in order:

God Mazinger is related by name only and Mazinkaiser is an OVA retelling of earlier Mazinger stories, based partly on designs created by Nagai for the Super Robot Wars series of video games and also on Nagai's original Mazinger manga stories.

Mazinger-Z also featured in a video game for the Genesis/Mega Drive. It went by several names like MazinWars and MazinSaga.

Throughout the storylines, common characters and traits tie the series together.

Except God Mazinger, the other mazingers share a very distinctive physiognomy, though the proportions and overall presence is modified in each one.

Mazinger Z usually looks shorter and wider compared to Great Mazinger, who has a more slender physique. This is mainly due to the "helmets", which is how one really can tell these two apart. The helmet of Great Mazinger is pointed while the top of Mazinger Z is "flat-topped". MazinKaiser looks more heavily built than either of them, and sports the typical over-detailed (more ornate) style of more modern mechas (consider there's a 30-year gap between the first two and him). MazinKaiser is also the bigger/taller of the three.

The main colours are always black (torso, hips, shoulders, sometimes limbs), white ("steel colored") (waist and limbs, with slight variations towards light shades of yellow and blue tones depending on the version), very dark blue or almost black, depending on the depiction (face, limbs) and red (chest plate and flying devices). The head is usually steel/grey, with a cavity for the ship that controls the mecha.

This cavity becomes increasingly complex in each incarnation. Mazingers have characteristic horns at each side of the head where the ears would go on a human head, always coloured yellow, the eyes are yellow with the exception of Mazinkaiser SKL which has blue eyes. The face is completed with a mouthplate with several narrow apertures on it.

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Wikipedia