Super Saiyan Blue is a transformation that uses the power of Super Saiyan God with the Super Saiyan form. This form can be accessed by absorbing the powers of god and combining it with Super Saiyan or through vigorous ki control training as seen with Vegeta in Super. This form exceedingly surpasses its predecessor, Super Saiyan God.
The concept of “Super Saiyan God” was first shown in the movie “Dragon Ball Z:Battle of Gods” And then Akira Toriyama expanded this concept for the next movie Dragon Ball Z: Resurrection ‘F’. As goku mentioned in the movie that this form is a result of a saiyan with power of super saiyan God further transforming into a super saiyan.
Many otakus think why goku used Kaio-Ken in Super Saiyan Blue form but not in any of the other Super Saiyan forms that’s because this God form requires a calm mind and intense training to aquire it due to which the formula was to use minimum amount of KI. Since the form requires a lot of focus and a calm mind it allows the use of kaio-ken.
The manga stated that this form had a major flaw in its stamina, not that the user gets tired way too fast when they use it since they lose any at all when in the form but that if the user uses it consequently several times the user wont be able to use even the 10% of the form’s power this explains why vegeta was easily beaten by HIT campared to goku who reserved this form until the end
How much is Blue form stronger than the Red one? at about 10% of the Super Saiyan blue’s power gets equal to Super Saiyan God (RED) form
The orignal design of Super Saiyan God mode was meant to be a lot more muscular while also wearing a cape but Toriyama disagreed and said that the form was going to be a lot more simpler
Mr. Toriyama orignally intened on making the hair of the Super Saiyan God, Blue but it had a conflict with the hair color of a future enemy that we thought would be Goku Black, so he ended up using blue for goku the reason behind that was that blue color showed attaining a certain limit that shows both strength and tranquil.
Aquiring the Form:
Vegeta aquired super saiyan 4 form with the help of a machine and aquires the Super Saiyan God with his own training while goku did not use the machine to achieve super saiyan 4 but achieved the Super Saiyan God with the help of others
In the anime it has been shown that goku’s wounds get healed after beerus stabbed him in the chest which gives the viewers a hint that the Super Saiyan God has a healing factor however this scene was never fully explained later on.
Super Saiyan God and Frieza:
The Super Saiyan God was first mentioned by frieza in the special manga writted by toriyama which means that frieza knew about the Super Saiyan God even before Beerus.
Toriyama says that if beerus Is 10/10 in terms of power then WHIS is 15/10 and goku is 6 out of 10.
It is hinted in the anime that you don’t necessarily need the ritual to obtain the power of Super Saiyan God or even be full bloded saiyan to achieve it, As shown by future trunks in his blue and yellow aura form.