TPK is short for Tele-Pathics and -Kinetics. Furs who are able to read/write minds and be able to move matter with a thought are considered "TPK Active." Empathy also follows under TPK.

There is a psudo-logarithmic scale for TPK strength. Each level adds abilities, but the numbers of furs at that level decreases.

Level 1 furs can only detect TPK activity. They are considered Sniffers.
Level 2 furs can detect TPK activity, read "unencripted" or "public" Telepathic messages, and "write" or "broadcast" them.

Furs starting at level 3 can block psychic "attacks" or constant intrusions. The stronger they are, the longer they can sustain the attack.

Level 3 furs can do pinpoint (person to person) "private" messages.
Level 4 furs can locate objects using telekinetics within a limited range.
Level 5 furs can apply a force to those objects within a limited range, but can locate objects over a larger range.
Level 6 furs can apply force to objects with a large range, and shield objects (including themselves) so no harm can get them. They can also vibrate the air around them in small pockets, producing an out-of-body voice.
Level 7 furs can concentrate at multiple objects at once, while holding intelligent conversation. These furs can fly. For fun, they produce their own echo.
Level 8 furs can enter a persons mind and rewrite it. All Level 8 and above furs are required by law to enter the medical fields. Level 8's however start to "hear" a very low background telepathic "hum". Some level 8's have a remote viewing capability, but it is considered unreliable.
Level 9 furs can fully enter another fur's body, seizing control, leaving their own body in a coma-like state, and re-entering it. Level 9's also have a reliable remote viewing capability. Level 9's have a "louder" background telepathic "hum" that requires training and concentration to block. Level 9's can also privately hold multiple telepathic conversations, and with training enter into a Level 10's mind. Only Dr. Mikail Markov ? has tested at level 9.
Level 10 furs can split their focus, implanting copies of themselves into others, while retaining control of their own body and abilities. A Level 9 with training can safely read a Level 10 without going through a "proxy crystal" (used for everyone else's protection and required by law to be worn by the Level 10 fur) -- a Level 10 looks like multiple Level 9's. Only Polymorphic Level 10's can overcome the telepathic "hum" by inverting half the hum, canceling it out; non-polymorphic Level 10's quickly go insane over the increased "hum" depending on how many furs the Level 10 can handle at once (thus the designation Level 10-x, where X is the number of furs that can be handled). WolfSkunk RedWolf ? is at least a Level 10-I (where I stands for Infinite).
Furs over a Level 10 are theorized to be demigods or seraphs, with the ability to change the quantum brane with the full capability to control the programming of the universe. They can handle the hum like it was multiple conversations and they were clones monitoring each one. Much debate as to what should be a proper response to a seraph.

Resistance Time Measurements

Measurements were taken by having a Level 8 fur psychically attack up to 16 furs, one at a time, in closed sessions. The break-through indicator was to have the fur stand up and say "something" in German. Level 6's and above were confined to quarters while the attack was underway.

Levels 1 and 2: None (no ability)
Level 3: Minutes
Level 4: Up to one hour
Level 5: Up to four hours
Level 6: Up to half a day
Level 7: Up to a day and a half.
Level 8: Up to a week.
Level 9: At least a month (reported, not tested -- end time was reported when subject Mikail Markov ? found the attacker and throttled her.)*
Level 10: Theorized to be up to a year, although may be more. No test has been performed.*

(* There are only one of each level so far, so testing was not done. When more are born, tested, and trained, data will be discovered to adjust these figures.)