Well since we are going to be dealing with a huge chakra cost here. how about a means of monitoring the available chakra?
20% of total chakra to summon, + 5% to keep it controlled, putting the user down to 75% of his total chakra.
Now...given you cannot exceed a minimum amount of total chakra in order to sustain life...what is that min?
Which would make only what % available for use?
To have chakra cost mentioned without a means of actually measuring and monitoring the chakra pool is going to be pretty pointless and just hyperbole. More of a 'for show' drawback that has no real world application. It makes it look like it would be tough, or a hindrance...some inherent flaw...but in reality it is just talk.
I think it would be cool to see, if a user falls below a certain total available chakra level, the genjutsu will fail and the beast will go into the drawback state mentioned of attacking their summoner.
It would take numerical limits and a finite series of jutsu/moves that can be performed with a varying chakra drain, creating a curve that would look something like a wave. Such a thing is not widely used in SL RP, and would likely have to be eithre invented from scratch or introduce a whole new system for zoning in general. Without there being general guidelines for the actual fighting (that proposal was soundly shot down) doing anything more than % would require revisiting the regulating the fights themselves part.
Respawning of summons bijuu due to character death.
Summons do not die when a contract holder does. I understand you are not saying this is what happened to the bijuu summons but are trying to account for what to do with it. But this scenario doesn't sit well with me. Too many variables. who controls the respawning event. How will it all be handled and so forth.
I propose that in the event of character death while a summons bijuu is called or even when it has not been called forth, it just goes to the council and then defaults to the stripping rules as to how they handle it.
But...let's say the bijuu is summons...called forth...and the challenger kills the host. HE has to deal with failure to extract the bijuu from a live host...is this being held to anymore? or ever? Once upon a time in my memory land, if you killed the host the bijuu respawned?
anyway...so you might have a respawn going on for failure to extract bijuu from a live host...and a freed summons with no host to turn on that suddenly sees the challenger as the next best target to vent its rage upon? And have an immediate attack situation on your hands too.
So it is a precarious situation there. Would/should/could the challenger be offered the opportunity to fight to capture that freed summons right then and there...provided it had been called forth and on the field during character death? And who controls that freed summons during the battle? The dead host player?
IS this too much BS and just match over...skip what might actually be going on in RP and just council bound for both bijuu? I am seriously against being able to extract a bijuu from a dead host. I know...side topic but here is where it came to mind for me.
Out of character, I think killing the host should be the primary objective, if I understand correctly. Kill the host, take the tattoo or whatever mechanism that we settled on, and then be the new master.
In an IC situation I guess something a little more "logical" would be needed, dependent on the state of the beast at the time of the original summoner's death. If never summoned, then tattoo/contract theft/inheritance goes as if the challenger won the match. If the beast had been summoned and had not been taken away prior to the death of the challenger, I imagine allowing the champion to GM the beast for the remainder of the fight is the quickest solution.
Not necessarily the best though. That's all I can think of at the moment though regarding that situation.
*P.S
If the summoner was ALSO a host, then the beast that he/she was hosting would go to the Council in the case of host death in an IC situation. In an OOC battle isn't that counted as a victory for the challenger?