OOC: Man, you're fast! I don't think I remember seeing any GM write so much and so concisely in less than a day - aside from Sean Mirrsen and Draignean, of course.
Also, what exactly does shapeshifting do - does it let the demon enhance its combat strength against mortals? What about spirits? Can it be used for infiltration and espionage?
Klaus's master once told him that a summoner's first powerful demon had to be a good, reliable fighter to protect them if any further summonings went awry, and nothing Klaus has ever read since gave him reason to think otherwise.
With the book still in his hands, Klaus mulled over the choices he had, trying to imagine what each demon would be like to deal with.
Rhithlale looked too weak for guard duty. Most likely, he would barely hold his own against even another lesser djinn. The idea of binding such a poor combatant as a guard seemed like an impractical waste of time. Klaus placed a bookmark on Rhithlale's page in case he ever needed a good shapeshifter, though.
Cruel, barbaric Skelkela would probably cast some overkill vaporize-everything-in-the-room spell the moment he had the opportunity, which put him about as far from 'reliable' as a demon can get. Its only viable application would be a one-demon-army sent on faraway missions: the collateral damage from its attacks would be too high for anything but itself to survive the battle. Even so, Klaus was sure he'd find a far better demon for this purpose if he put his mind to it, and didn't make an effort to remember Skelkela's summoning spell at all.
Now, the parts concerning Fisrusk didn't mention whether 'proud' stood for 'honorable' or 'arrogant' in its case, but Klaus preferred to hope the demon had at least a bit of the former. A spirit that keeps its word is much more trustworthy than the one that only looks out for its own profit, after all, and you don't live long without a loyal bodyguard. Besides, Fisrusk was the strongest fighter of all three, and Klaus thought the demon might be worth the trouble even if it had no concept of honor.
Go upstairs to my room and practice, practice, practice the binding of Fisrusk.