Have you put one point into Summon Resist?  That helps immensely to keep
the skels alive through those fire circles..
A lot of people like to Iron Maiden big D and just keep recasting the Clay
Golem on the opposite side from you.
There should be no 'limit' to Revives, especailly in SP.
Personally I like to get the Fire Golem - he lives thru those fire walls
ok - and just Decrep D and be ready to recast the FG, on the other side of
D of course.
Normal Diablo will probably be your toughest fight until you get to Hell
Baal.

Forget the stuff you can summon - They're all toast for normal Diablo.

Repeated castings of Clay Golem and Iron Maiden are your good buddies.

(Along with lots of potions to feed to your merc)

As far as I've been able to figure out, "supporting" the max number of
revives means "Can you and/or your skellies/merc/etc" kill enough things
fast enough, and can you keep up a supply of mana to be able to cast
revive often/fast enough to get to/maintain the max without having the
first ones you made drop dead of old age?"

(Remember: All revives die 180 seconds (3 minutes) after you make them -
so if it takes you and your "posse" 3+ minutes to kill off the max
number of things, or you can't keep up enough of a mana supply to cast
enough revives during that time, you're not going to be able to
"support" the max.)

The question is how many points do you have in skeleton mastery?

I just finished normal diablo in hardcore and it wasn't that hard (in the
interest of full disclosure he killed my last skellimancer).

Pre-Might Merc I find the archer merc pretty good against Diablo, in my
battle against him the first thing I did was cast decrepify, then put my
clay golem in his face, between my ice mages (2 of them), and the ice
arrows, with decrepify and clay golem he was pretty slow, and the battle
wasn't ever in question.

What level are you?

Most mercs are useless against Normal Diablo.

A necro can solo Diablo at level 12 with CG and IM alone.  Difficult
in HC, but purely a matter of perseverance in SC.  Just make sure you
always have a tp to go back down.

"Not even _my_ death can save you from me!"

-- Roy L

Besides the summon resist, there is also a tactical advice from me:
Leave a seal closed where no monster spawns when opening it and prepare for
Diablo before you open it. Whe you are ready, open the last seal and run to
the points where Diablo spawns. You will be tehre before he is. Always keep
him between you and the most of your minions. This way he is always in melee
mode and doesn't cast his rings of fire. Your skellies will die, but one by
one over a longer time. Curse, recast golems and feed the merc until Diablo
dies.

HTH
Rudi

Forget the merc. He'll go down faster than <insert rude joke here>.

Normal Diablo always gave all my characters shaky hands. For a
skelliemancer, you can try a few things.

Hopefully by this point you have at least one point in Decrepify, and
one point in Summon Resist. You can create a "summoning" set - a set
of gear you wear to summon your skellies since they retain the skill
level they were summoned at (then switch back to your battle gear).

You're SP; you can shop a +2 to Necro skill levels wand at Jamella's.
(Lore RW hat if you're lvl 27, and can make one.) Voodoo handbags that
drop in Act I Normal can have awesome stats - I think one of mine had
like +3 to SM. Another had some bonus to the clay golem.

WP around until you find one with a Skills Shrine near it. Put on all
your summoning gear, hit the shrine, and summon. If you lose any
skellies in battle, re-gear summoning set, and hit the shrine again.
(Yes, it is tedious, but even, in terms of +skills, you only have a +2
Necro skill levels wand, that one point in Summon Resist is now four
points, and it makes a huge difference.)

The minute your screen starts shaking, RUN to the center pentagram,
and place
your army in the middle of it. I have found that Diablo is less likely
to send
out that Fire Nova if you start the battle close to him. The minute he
appears,
slap Decrepify on him. Make sure your clay golem is hitting Diablo
(sometimes he
can get stuck behind all the skellies). If he is stuck, re-summon him
on Diablo,
who should now be slowed significantly. Recast the clay golem as
necessary. Keep
Diablo Decrepified at all times.

Good luck!

--
Jill

Most important thing you can do as a skelliemancer is CLAY GOLEM  he
slows all bosses by 50 percent . If he dies pop up another one . My
Current necro 78 on the useast necro ladder and climbing is level 94
raises 17 skellies, 17 mages, 43 revives, 1 golem , 1 oak sage and 1
poison
creeper.
I'm putting 20 points in each skelly mastery . skellies , mages ,
summon resists and revives. 1 point each in all 4 golems ,  golem
mastery amp damage , corpse exp. and
teeth .
Corpse explode is important 4 maggot
lair .                                                          Clay
golem is for all bosses once he gets hold of a boss they normaly stick
in place giving your zoo a chance to kill
him .                                                            1500
in mana means you can keep summoning resists all day long and the
skelly or mage you lose here and there . But i dont lose many with the
72 all resists they have from maxed sum
res .                                                               At
level 94 i still have 2 points left to put into my revives and 1
points into summon resists leaving 2 points into other
skills                                                                                                           .