When fighting the manticore a good strategy is bring in high level Rex's with good saddles and circle the manticore it then becomes pinned allowing you to kill it without it flying all around .... watch out for the poison it shoots at you though it will kill you off your mount like the poison wyvern ..
Bring around 6-7 or more rexs and when it lands everyone get around it and trap it. Deathworms will come and knock u back but just keep moving forward slowly so u dont get pushed out. Even when the rock golems come don't stop hitting it. Goodluck boys :)
Just dont run, its fast and will catch you, bring VERY high lvl stuff. It has one weakness for taming: FORCETAME!!! So many tries to kill this thing, and every time I die. Every time I die I always say "Mission failed, I'll get em next time" But i still cant beat this thing... HELP