Version 1.2.3. I have added some features regarding the disposement of Co-Emperors. If you decide to dispose them, they will get a weak, inheritable claim on the Empire. In addition, they will get an event to upgrade it to a strong, inheritable claim. AI's chances of doing so is affected by their traits and their opinion about you. So, you'd be cautious when choosing your colleage. Also fixed a problem where Greek Symbasileuses had their title displayed as Mitkaisers (German version). This version Might be buggy. If you find any bugs or glitches, please let me know immediately.

Version 1.2.2 Hotfix: making AI prefer their heirs when considering a Co-Emperor appointment.

Version 1.2.1. Hotfix: the opinion penalties for tyrannical Co-Emperor appointment is no longer stackable. No more -240 crazily furious vassals!

Version 1.2: Revolutionized! - Adds more freedom (and following costs) to the appointment of Co-Emperors!

• Now, your children can become Co-Emperors even if they are not yet adults, reflecting the historical fact that the symbasileus appointment followed directly after birth of an male heir. They must be allowed by the gender laws, though (just like the imperial election).
  
• The Co-Emperors will get the council position within 1 year of being adult and not being incapable, via a decision they will always take whenever possible (if you play as a symbasileus, you have to enact that decision yourself).
  
• Now, you can appoint your Co-Emperor as one of the five councilmen, via a specified decision.
  
• You can now appoint any of the emperor-election candidates as Co-Emperors, without first making them the heir to the Byzantine Empire. However, this will induce a serius prestige damage and a severe vassal opinion panalty. (Reflecting a suggestion by finrod)
  
• Now, the disposed Co-Emperors will have a decaying opinion panalty against the Emperor. (For obvious reasons).
  
• Reflecting the vanilla game's title localization policy, I have specified the Co-Emperor title dynamic names are only used for the following cultures: Greek (not any other culture in the Byzantine group), Roman (not any other culture in the Latin group), German (not any other culture in the central germanic group), and Russian (Newly added! - an hommage to the historical Dual-Tsarship of Peter the Great and his older brother Ivan V).

1.1.2 Critical bugfix where the byzantine symbasileuses does not get purple-born children.

1.1.1 The thumbnail image was replaced.

1.1 Now the title of Co-Emperor is tied to the culture of the emperor, not on the title of the empire (Byzantine vs Roman Empire). This reflects the change of the title system of two empires as of the Holy Fury update. If the emperor is greek (or byzantine group), then it's "Symbasileus". If the emperor is Roman (or latin group), it is "Caesar Nobilissimus". If the emperor is german (or central german group), it's "Mitkaiser".

1.0.2 Critical bug fix.

Ver 1.0.2: Now Symbasileuses have vote not only in the council but also in the imperial succession. In addition, The symbasileus / co-emperors has a higher chance of being voted by the other voters. The amount of bonus is equal to the amount of bonus that goes to (honorary title) Despots. Now, Symbasileuses and Co-Emperors are considered unique titles, and they cannot be granted any other unique honourary titles (such as Despot, Caesar, etc.).

Ver 1.0.1: Minor bugfixes.