Misty Isles Kitten Power and Morale.

 In Palace of the Vampire Queen felines are a bit unusual.

The basic Cat from the Monster Manual

From the Monster Manual

After reading the module the Lynxes and Domestic Cats in it have the additional powers. Based on how both the Domestic Cat appear in the module and the specifics mentioned on Lynxes, cats are a bit more magical and or psionic than presented in the Monster Manual.

* All cats can detect evil within 12 feet.

* Kittens will develop telepathic communication with keeper.

* Carriers of Kitten add 3 to morale score.

I ruled these abilities apply to both the Lynx and Domestic Cats from the Palace as it makes the actions of the domestic cats make sense. The felines in this setting are far more likely to posses unusual powers in this world. 

Morale is an older rule from Chainmail and Original D&D. 

When in highly dangerous situations morale was checked. I asked my husband also an old time DM if he remembered ever playing this way, and he did as well. So morale checks back in the day applied to everyone. Any creature in battle may try to run away or surrender, thus everything living with some form of intelligence has a morale score. As the game progressed Morale stoped being applied to PCs, however if you think about it these are the original fear, sanity rules for PCs.

The morale check is rolled against the morale score, it is rolled with 2d6, I think we all eventually used d12 for this. The 2d6 gives a 2-12 range, dividing 12 into 100 = 8.333 to infinity so rounding down 2 equals about 16%, with each additional number representing another 8%. 12 = 96%. 

Morale Scores were assigned to monsters. Monsters with a base score of 2 would always try to retreat. In latter rules of Basic which is Original D&D more or less, a score of 12 meant the monster would always fight to the death. There was one Basic edition that indicated a roll check of 12 meant the monster would become fanatical and fight. This could be amusing. Naturally modifiers could improve or decrease morale of monsters and followers, and when The Misty Isles material was produced players too! 

These kittens thus are pretty powerful as they boost the PC or any NPC becoming bonded to them morale by 3! That’s a 24% increase to not loose heart or run away in Panic! Using the chart from the Rules Cyclopedia below you can see the boost of +3 is significant.

 An easy way to apply morale checks to PCs using the old system is to use their Charisma modifier for Retainer Morale for the PC as well. Shazam! Sanity rules found using existing rules! If you go ahead and allow a roll of 12 to equal frenzied state for player, as a DM you can grant cool actions such as extra attack, or doing extra damage, regain some hit points or what ever makes sense for the PC to be able to do in “the rule of cool” way.

Fast forward to 5e most “fear” type saving throws are Wisdom based in 5e. The DMG for 5e goes on to suggest a new ability score for Sanity. It also suggests using an Intelligence check for Sanity, a Wisdom check for Fear, and a Charisma check for Horror. In addition the DMG does discuss Monster Morale as a Wisdom based saving throw. My thinking is the Kitten Power should be applied to the appropriate saving throw that would have been covered type of moral check causing scenario in the past. Since these checks involve meeting or exceeding the DC set by the DM the Kittens 3 would indeed be added to the players roll. Purriful boost that is.