It's a dangerous life

So, we'd just got everything ready for our rescue mission to the volcano, and were about to set off, and were just waiting for Jingle and Diffy. Diffy came down first, struggling to zip up his rucksack.
'Diffy, you will NOT need that many toblerones.'
'How jyou know? I mite dooo. Anyways it Chrismas. And they's yummy.'
'Well one, we're going to a VOLCANO, chocolate may not be the best choice, and two-'
I saw the look he was giving me 'Fine, bring the toblerones'
'Igonna. I not fink of it being hot tho. Can you freeze em if they goes all melty?'
'Uh, if we're not running for our lives at the time, then yeah.'
Jingle came down then, tucking a tree decoration into his pocket. 'Sorry, I've been practising this thing with Chestnuts, and I think I've got the hang of it.'
'Sounds good. Right, are we all ready to go?'

'NOOOOOOOO!'

A booming voice filled the base, and a huge wind picked up, almost knocking us over. Thunder and Lightning began to rage outside, and the door blew off it's hinges. A shadow appeared in the doorway, looming over us. As it moved closer, the light inside the base revealed it to actually be a fairly short man, maybe around 30, who scuttled nervously inside, looking round at all of us, and panting.

'Sorry....ran here....didn't want to miss you......not too late.....good......hi....'
'Um, hi? Sorry, who are you?'
'Oh yeah.....call me.....Clarence......got something to show you......need your help....don't go, please.'
'Right. Well, Hey Clarence, nice to meet you, but we're about to set off on something REALLY important, so maybe we can leave you in the capable hands of some of our new recruits (Sorry readers, I haven't introduced you yet. This will happen soon) who are looking after the base while we're away, and we can-'
'NO! I need you all to stay. You need to be here at Christmas.'
'Well, with any luck we will be, we've got a quick in-and-out route planned, this should just be a sort of smash-and-grab situation, so hopefully-'
'NO! It will take weeks, and if you aren't here at Christmas, well, it doesn't bear thinking about! But of course I can't STOP thinking about it, and I can already see the whole thing, and oh, please don't go!'
'um...but, we wanted to get them home for Christmas....'
'No! Too late! Please, believe me!'
Everything went.....wobbly, and bright, and we saw......things. Darkness, and storms, and a world consumed by grief. And the noise! Crying children. sobs and wailing filled the night. It was a world without hope, full of lost souls drowning in their own misery and woe.

The vision faded, and we found tears in our eyes. 'Please, stay, you have to be here.'
I nodded, sniffing. 'What do you need us to do?'
'Just be here, and offer help when it's needed. You have to fill a void left by someone you all know. One of his followers will come here, and you have to be waiting. I-'
Clarence clutched his head, groaning. 'Argh, if only I was fully trained at this, I could resist better...so many possible futures....so many pasts....you guys are really something aren't you?'
Jingle ran forward to help, pocketed ornaments ringing and tinkling as he went. Clarence frowned. 'Great, I bet that was Cas. I better get mine soon. Don't...' he swayed a little. 'Don't let me down....V...H....-'
He never made it to S. He collapsed, and has been comatose ever since. That was a week ago, and there's been nothing from him OR this mysterious 'follower' we're meant to help.

What do we do?