Situation: I've Summoned Monk Fighter (only monster in the Monster Card Zone) and have the trap card Lone Wolf set previously and play it.

Question: Since the Monk Fighter/Lone Wolf combo keeps Monk Fighter from being destroyed in battle... do I still take Life Point damage when a monster with more ATK points attacks Monk Fighter?

Nope, you still don't take any Battle Damage, as per Monk's effect. Lone Wolf only means that he isn't affected by your opponent's effects (I'm assuming that's why you're asking ^^)

Here're the Netrep Rulings:

Rulings

1. [Re: Lone Wolf] "Archfiend of Gilfer" and "Dark Necrofear" in the Graveyard can activate their effects and target "Monk Fighter" targeted by "Lone Wolf". This is because they activate as Monster Cards, equip to the target monster, become treated as Equip Spell Cards, and THEN apply their effects (by which point they are now treated as Equip Spell Cards).

2. [Re: Lone Wolf] "Your opponent's monster effects" on "Lone Wolf" means "the effects of monsters that your opponent controls". So if your opponent uses "Monster Reborn" on your "Exiled Force", they still cannot Tribute "Exiled Force" to destroy your "Monk Fighter" targeted by "Lone Wolf".

3. [Re: Lone Wolf] If you have "Monk Fighter" targeted by "Lone Wolf", the following are examples of monster effects that will NOT be negated because they are not applied to a monster: "Airknight Parshath" (damage is inflicted and a card is drawn), "Fiber Jar" ("Monk Fighter" is shuffled into the Deck), "Maju Garzett" (the ATK of "Maju Garzett" does not become 0), "Susa Soldier" (the damage to Life Points is still halved), "Dark Magician Girl" (her ATK is still increased by her effect), "Stone Statue of the Aztecs" (Battle Damage to your Life Points is doubled), "Amazoness Fighter" (opponent's Battle Damage to their Life Points is still zero), "Amazoness Swords Woman" (Battle Damage is still redirected), and "Reflect Bounder" (you still take effect damage to your Life Points).

4. [Re: Lone Wolf] If you Summon "Monk Fighter" and target it with "Lone Wolf", and your opponent controls "Bug-Tusked Mammoth", you can still attack that same turn with "Monk Fighter".

5. [Re: Lone Wolf] If you target "Monk Fighter", etc. with "Lone Wolf", and "Monk Fighter" is later flipped face-down, the effect of "Lone Wolf" disappears and is not re-activated even if "Monk Fighter" is later flipped face-up again.

6. [Re: Lone Wolf] If your opponent Summons "Dark Jeroid" and reduces your "Monk Fighter" ATK by 800 points, then later you activate "Lone Wolf" targeting the "Monk Fighter", it does not restore the ATK of "Monk Fighter".

7. [Re: Lone Wolf] The effect of "Lone Wolf" will be negated by Jinzo even if targeting "Monk Fighter".

8. [Re: Lone Wolf] Your "Monk Fighter" targeted by "Lone Wolf" cannot be destroyed by the effect of "Tribe-Infecting Virus". Furthermore, if it is the only monster on your side of the field, your opponent cannot discard cards to activate "Tribe-Infecting Virus" to destroy Rock-Type monsters, because it will have no effect.

Sheesh... thanks... I need to learn to read the dang cards. I was focusing on the trap card and didn't add in Monk Fighter's effect.

Other related questions I have to Monk Fighter and Lone Wolf:

I read the effects and see that I can only set Lone Wolf when Monk Fighter is the only monster card on my side of the playing field. Lone Wolf is a continuous trap card.

1) Do I void out Lone Wolf if I Summon/Set another monster later? (The way I interpret it NO... but I'm unsure.)

2) In the same turn can I turn over Lone Wolf and then Summon/Set another monster?

Thanks in advance for answering (so I don't spam with just a "thanks!")

Actually, you can only ACTIVATE it if there is only 1 monster on your side of the field (activate and set are two different things).

1) No, if you have Lone Wolf active on a Monk Fighter, Master Monk, or Chu-Ske the Mouse Fighter and then Summon/Set another monster, the effect of Lone Wolf stays.

2) Yes, you can Summon/Set a monster during the same turn that you activated Lone Wolf.