Summary: You don't have to beat the S tourney to fight in the Greatest-5 if you've already won the last fight. (perhaps even just unlocked them)
You don't have to beat all the Greatest-5 to fight the 'Big Nasty' final battle if you've previously beaten it. (perhaps even just faced it)

(no I don't feel like saying the name or type of the critter and spoiling it. I'd love to be able to raise it though.)

I beat the game with my little Suzarin/? (the blue one from one of the pandoras)
Later I took my pirate henger (whatever the henger/goat is called) and fought my way up.
I beat the A battle, and well I was trying to get money so just for fun I tried one of the Greatest-5 battles before I beat the S tourny, figuring it'd say no like in MR2. I was wrong, it let me fight.
Interestingly enough also before I beat all the Greatest-5 my assistance said in the appropriate week that I could fight the big nasty monster (the last one you face before the credits the first time). My henger hadn't beaten all 5 greatest-5 (And wouldn't, it died after 4) but I was allowed to fight the big nasty.
I was surprised because this runs counter to what Grandpa B. said previously if I wanted to face it again.
Anyhow if anyone cares to confirm this it would be good for others to know.
Specially since the Greatest-5 are worth 10000 coins every time you beat them, good way to make money while raising a non-money maker.

I managed to beat one "big 5" tourney with one of my monsters in my "old game" (grumble grumble darn bug grumble), and that's it... but then with my next monster, I didn't have to beat the regular S-level tourney to get the the big 5 again. It just seems to be a one-time-unlock-necessary thing.

My gosh Trickster 0_0

You had to restart? Geez... sorry to hear that. >.<

Yeah, hit the bug in Kalaragi and didn't save at just the right spot... ah well. (Read the warning from Lisa if you don't know what I'm talking about. Quickly, I might add.)

I'm mostly better now... *sniff*

Or at least, I'm building back up. My wonderful adorable Ogyo just died, but at least I've got a rare (possibly unique?) Durahan to replace it... *sniff*

(How can a fish be so cute?)

Now... the question is...

Why'd you lose to the person in question anyway (forgot his name - I read if you lose to a rival this bug is triggered)

Surely the almighty Trickster wouldn't lose that easily... :P

Haha... nothing like poking fun at the 'higher ups' ^_^

*poke*

Actually my monster at the time was pretty good, I just had a really bad fight at that point for some reason.

Not that I don't lose lots of other times. :p

Heh. I know what you mean. Even the best monsters can be very unlucky sometimes. Thank goodness they included a soft reset in the game. ^_^

(Stupid Dark Cloud, not including a soft reset... >.<)

Since this is a post about the Big 5, I have a question about it. OK, so I have a henger that beat S class and I think can beat at least one of the big 5. I'm not sure when he's gonna die. So I heard that you have to get invited to fight one of the big 5. Now when does my henger have to be on the ranch to be invited? I don't want him to die before at least trying to fight one of the big 5. I'll appreciate it if anyone can answer this.

The Great 5 are on the tourney calendar, they look like unofficial tourneys in the S portion of the grid. I could be mis-remembering this, but, my monster was at 4y8mo when he beat the S level official cup, and I was worried too. I froze him, and hauled him out a week before each tourney, rested the week before, saved, then battled. It all went pretty well. I lost one, but reset and won it. Freezing didn't seem to affect him much. Now the battle afterwards, that one is on May2, but you have to be on the ranch on the first week of May so that when the week rolls over, you get the invite. I froze my monster until then too, and he was able to win.

Oh, I thought those unofficial tourneys were just for money with the S class monsters that you had to beat. So those are actually the big 5? I guess I didn't feel like fighting more monsters and I didn't really look at what the tourney was about. Thanks for the info. Got to go and try beating one of the big 5.

i seem to remember that the unofficial [big 5] s level tourneys did not appear on my tourney calendar until i had won the s level official. now that i have won that, they appear and i don't have to win the official tourney first.