[hleV]

You could get rid of ESF Models module by writing this in your code because that module does the same.

#define MDL_SATAN "models/player/satan/satan.mdl"
 
new g_iMaxPlayers;
 
public plugin_precache()
        precache_model(MDL_SATAN);
 
public plugin_init()
{
        register_forward(FM_StartFrame, "fwServerFrame");
 
        g_iMaxPlayers = get_maxplayers();
}
 
public fwServerFrame()
{
        static iCl;
 
        for (iCl = 1; iCl <= g_iMaxPlayers; iCl++)
        {
                if (!is_user_alive(iCl) || !is_user_satan[iCl])
                        continue;
 
                fm_esf_setmodel(iCl, MDL_SATAN);
        }
}
 
stock fm_esf_setmodel(iCl, const szMdl[])
        engfunc(EngFunc_SetModel, iCl, szMdl);

P.S. I'm afraid there's no better way of changing model than doing it on each frame. And it sucks. I hope things will change in ESF 1.3.

Oh and... Shouldn't is_user_satan[] be a boolean?

new is_user_satan[33];

change to

new bool:is_user_satan[33];