Help with Kirin

where is his weak spot?? and which katana is better agains him? I have :

-Ogre Slayer (Ogre destruction Slash katana it's the literal translation)[the 2nd thunder katana]
-Dragon Katana <焔> (the first Crimson katana)
-Military Katana -> The Nana Katana
-Flying dragon Katana<Blue Leaf> -> 1st Poison Rathian Katana

also, what are those yellow ? items? If I get one my life drains...

this item is a flag, you have to keep it and go to area 8 (in mountain), then climb the cliff until the highest point (with a mat for flag) (to go there, go through the little hole in the wall, then climb to the dragon skull and then climb on the left hand wall), then try to use this yellow item by pushing sqare button around the mat (not right near, you have to try on the whole plateform). congratulation, you have complete the Asub quest

My setup when I fought kirin is Gypceros "S" set w/o helm and PBA, average 30 Min.
IMO any decent weapon with green or better sharpness, armour wise high lightning resist is favourable.
I checked stats on kirin and it appears that it's has little elemental weakness, if any it would be fire or water. It's weak point is it's horn, striking it's head from the sides do not always count as a hit on it's horn. While a friend of mine likes to use lao shan hammer on the kirin, it's hardly of any use besides it's high damage. I'll recommend you to use any other slashing weapons unless you intend to train on kirin for the training mode quest.

and beware of her fury. when an halo surrend her, try to not be near cause it's painfull, just wait she calm down

so a great thunder resistance is better? nice time for do a Khezu massacre (Now I have a great fire katana MUAHAHAHA) and make his armor ( I only need make scars in all his body for a 8% of chance of get his "meat", and capturing him alive I will get another 3% chance, I know is low, but the rathalos plates are lower and by now I have 4 of those... [I'm sure that those are plates because their price is over 4000z])