How to make a Kamen Rider-like belt & suit?
 

If I was to fight crime and for justice, how do I create a kamen rider suit?

I thought to myself of making it something of.... kamen rider, batman, iron man, assassin's creed, megaman & bionicle. Mostly assassin's creed.

The belt is in need of helping with the transformation too.

The suit needs to allow me to change into any form that can suit certain environments and immunity.

In real terms, it's impossible? I mean technically you can make a rider costume with armour and all that but like to actually transform like a normal rider instead of riders like G3 is basically impossible atm.

A Bionicle Kamen Rider? Haha.

The main rider could be the tribal Kamen Rider Mata who's belt looks like a Suva (the top of the Mata canisters) and when he places a mask on the face of the belt, he gains their element, weapon, and ability.
Base forms: Tahu, Kopaka, Onua, Gali, Pohatu, and Lewa sub-forms (like Wizard styles.)
First power-up: Golden mask enhancements to each of the base sub-forms (similar to Kuuga.)
Second power-up: Nuva Form.
Final power-up: Adaptive Nuva Form.

The secondary Rider could be the futuristic Kamen Rider Metru who's belt uses Kanoka disks in a similar fashion. His final could be Hordika Form where he has to learn to control it's bestial nature (similar to Gills or Putotyra.)

:p

But what of making it a futuristic "Assassin's Creed" suit?

I can ride a motorcycle and take up a board for lava, snow, water, dirt & air.

Im gonna try to imitate Ryouma Sengoku a lil bit and propose this:
Ever heard of molecular particles? What if a suit was inside a satellite in outer space?
And Somehow the suit would be shot at the speed of light particle by particle to the user which summons it. The belt can be like a homing device for the particles and the suit would build itself around the belt? However, it would require a special type of alloy for the suits to withstand damage and be light enough to move freely. IDK just my crazy talk xD

Then the third rider could be the Voya, who's power ups are the Mahari and movie exclusive riders could be like Likahn, Glatorian etc.

I'd thought about that, but the Inika/Mahri just kinda don't fit as well. Not only do they change islands half way through, but it'd also just be weird for the power-up form to be randomly aquatic based. It just seems too specialized to me. But whatever.

Just get abducted by an evil organisation that wants to turn you into a Cyborg Bug Man. Easy.

Make sure you escape before they turn you evil though! That's the important bit.

Voila, you are the next Stronger!

I'd look at some cosplay tutorials on YouTube. There are a lot of talented costume designers out there that you can get tips from.