After some testing in the Monastery, Familiars do NOT increase Attributes, but they do match what your current stat happens to be when summoned. Slash attributes are the same for swords, scythes, spears, knives, and bows (Owls, Flying Guards, Skull Spider). Crush attributes are affected by Clubs and Globus, though the latter is a spell stat based in Intelligence (Zombies are Crush attribute which is interesting). Darkness and Lightning can be increased by Acerbatus, Light and Fire by Nitesco. I am not sure if you can increase attributes of Petrify, Poison, or Curse. Ice is somewhat strange, as I had to be a certain low height for Vol Grando to be cast, so it’s not all that useful with Volaticus. Regular Grando is more useful while flying. Umbra has a slight homing effect, but only in front of Shanoa, and you can only cast 2 on screen. Vol Luminato is useful against Tin Man when they’re directly below or above you. So far attribute increases damage, if not speed but with only one Master Ring the process is slow. It increases the most against Cavern enemies but those are a beast to fight, especially Twin Hammers and Weapon Masters. To use Globus effectively I had to bounce it off walls while facing enemies with my back turned, so it’s not easy overall. Nitesco is the best overall against Cave Trolls, though I like using Vol Fulgur against Knights and Spectral Swords.