Hi everyone! Here are some tips in making a Fiend/Spellcaster deck everyone 
must read, and I mean everyone--even guys who use Summoned Skull.

How To Start

If you're new to Yu-Gi-Oh!, it's best for you to get the Yugi Starter Deck 
to begin making your Fiend/Spellcaster Deck. Why? The answer is simple. 
Unlike the Kaiba Starter Deck, the Yugi Starter Deck has better Monsters. 
If you need Summoned Skull, this is where you'll get him. If you need 
defensive Monsters, the Yugi Starter has Mystical Elf (Yay Mysty!!!) and 
the Wall of Illusion. Mystical Elf has 2000 DEF and cannot be Trap Holed, 
while Wall of Illusion can return any Monster that attacks her back to the 
opponent's hand. Once you get the Yugi Starter Deck, now you need to get 
some boosters. Start with Metal Raiders. You'll find great Monsters like 
Magician of Faith (Brings back a Magic Card) and Dark Elf (Pay 1000 Life 
Points to attack with her) here. Magic Ruler will give you great Common 
Equip Cards like Malevolent Nuzzler (Increases ATK by 700 points; pay 500 
LP to put her back on top of your deck) and, if you're lucky, Maha Vailo. 
Pharaoh's Servant has nasty themed Monsters like Kiseitai, who is 
absolutely immortal during your opponent's Battle Phase. Okay! Have you 
gotten what you need? If so, let's move on!

Basic Deck Building Stuff

First off, try to make your deck as close to the 1:1 Monster to Magic/Trap 
Card ratio as humanly possible. Your Monster Cards are your most important 
cards, so you have to have as many as those as you can. For Trap Cards, 
Trap Hole is a must. Carry at least two, or even three if you have enough. 
For Magic Cards, if you have any of the staple "Limited" Magic Cards, put 
them in. These cards include Monster Reborn, Change of Heart, Raigeki, Pot 
of Greed, and Dark Hole. Now for Monster Cards! Fiend and Spellcaster 
Monsters are some of the most versatile Monster Types in the game, so 
putting up good Monster Cards shouldn't be so hard. One last thing: don't 
be afraid to have a 40+ card deck. The rulebook does say that if you have a 
40+ card deck, you may reduce the chance of drawing the cards you need, 
40+ but
keep this in mind: you need to defend your Life Points. If you're planning 
to make a big deck, you must have defensive Monsters and the right 
corresponding support Magic and Trap Cards. All right then! Let's move on...

Who Says You Need Summoned Skull?

Don't get me wrong--I use Summoned Skull too. He's a great Monster. But 
there are other great offensive Monsters available that you can use in his 
place, just in the off chance that you're afraid to lose him or that you 
only have one (Like me--please don't get mad at me!!!) Here's a nice list 
of good attackers.

1) Dark Elf

2000 ATK for a Level 4 Monster is very rare in the English Yu-Gi-Oh world. 
You have to pay 1000 Life Points every time you want to attack with her, 
but you can also leave her in Attack Mode, though. Slap some Equip Cards to 
boost her ATK and leave her in Attack Mode. She'll then become an offensive 
"wall" of sorts; warding off any weak attackers.

2) King of Yamimakai

He's a Common in Metal Raiders! Why aren't people using him? What's wrong 
with a one-Tribute Monster with 2000 ATK? Be glad you can get him more 
often than Summoned Skull, who's an Ultra Rare in this set!

3) The Bistro Butcher

He's a La Jinn who can make your opponent draw two cards whenever he does 
Direct Damage. You may end up helping the opponent get the cards s/he 
needs, but there's also the chance of decking him/her out faster than 
normal. Don't pass up on this guy.

4) Maha Vailo

Despite the fact that she's a Super Rare, Maha Vailo is possibly the best 
substitute for the Skull. And with Malevolent Nuzzler being a Common card 
in Magic Ruler, it's not impossible to make her an instant Blue Eyes 
Ultimate Dragon! One MN makes Maha Vailo a Level 4 Wingweaver, two helps 
her beat almost any Tribute Monster in the game available thus far, and 
three makes her strong enough to even take out Blue Eyes Ultimate Dragon! 
Need I say more? Maha Vailo is the best--period.

"Iyaaaannnn!!! Don't Hurt Me!!!" How To Make A Good Defensive F/S Deck

You can't keep an offensive in Yu-Gi-Oh! forever! With cards like Raigeki 
and Cyber Jar out there, if you also don't pack a good amount of defense 
material, you won't win. I definitely don't have a good amount of beatdown 
Monsters, so I usually put more high-DEF Monsters like Mystical Elf in my 
deck. To make a defensive F/S deck, first you will need good defensive 
Monsters. Mystical Elf is a must. You can get her really cheap in EBay if 
you can't find any Legend of Blue Eyes White Dragon packs. You'll also need 
to put in Wall of Illusion, since she can return Monsters back to your 
opponent's hand. In Magic Ruler there is Ceremony Bell. This allows you to 
see your opponent's hand--as well as you allowing your opponent to see your 
hand--when it is attacked and survives. And in Pharaoh's Servant keep a 
lookout for Bite Shoes and Kiseitai. Bite Shoes' Flip Effect let's you 
choose what Monster goes to either Attack Mode or Defensive Mode. As for 
Kiseitai, like I said before, he's immortal during your opponent's Battle 
Phase. This is because the moment he is attacked while in face-down Defense 
Mode, he latches onto the attacking Monster and equips himself onto 
him/her/it, becoming an Equip Card. During your opponent's Standby Phase 
you gain LP equal to half of the attacking Monster's ATK. Kiseitai is also 
great since you can destroy him and your opponent's Monster with Eternal 
Rest! To finish your defensive F/S deck, add in Magic and Trap Cards that 
support your defenders (Like Backup Soldier to bring Mystical Elves back to 
your hand) and a few high-ATK Monsters like La Jinn.

Try Adding Cyber Jar To Your F/S Deck!!!

It's not a Fiend or Spellcaster Monster, but Cyber Jar is a great addition 
to any deck, even F/S decks. Try putting in a few Magicians of Faith and 
The Shallow Graves in your deck so you can keep bringing back Cyber Jar. 
You can also form a nasty combo with Spear Cretin and Cyber Jar. Flip 
Summon a Spear Cretin, then try Flip Summoning Cyber Jar. All the monsters 
on both sides of the field (Including Spear Cretin) will be destroyed, and 
you can Special Summon Cyber Jar on the field face down! Of course your 
opponent also can Special Summon a Monster, but maybe you can take that 
Monster down by flipping Cyber Jar again.

A Look Into The Future--Labyrinth Of Nightmare's Fiends And Spellcasters

Labyrinth of Nightmare releases next year in February, and it promises some 
awesome Fiend and Spellcaster Monsters for you to add into your deck. Want 
another Change of Heart? Then maybe Dark Necrophia is your Monster. She 
can't be summoned unless you take three Fiend (Demon in Japan) Monsters 
from out of the Graveyard and out of the Duel. She has 2200 ATK and 2800 
DEF. Put her in Defense Mode, and if she is destroyed, she'll latch herself 
onto the attacking Monsters, becoming an Equip Card. That Monster is now 
under your control! There's also some Super Rare Earth Fiend/Demon-type 
Monster with 500 ATK and 2000 DEF. There are some more mentionable Monsters 
in the next set as well, but maybe I'll tell you about them in my next tip. 
But do, however consider packing a Compassionate Nun. If you offer her as a 
Tribute, you can retrieve a Monster defeated in battle back to your hand. 
This is great if you want to get Magician of Faith or Mask of Darkness back 
from your Graveyard! I'd like to give credit to Edo's Duel Monsters site 
for the info.

Well, there you have it. If you think Fiend/Spellcaster decks are nothing 
but beatdown decks, think again. You can also make defensive F/S decks or 
even F/S decks that allow you to summon Exodia much faster than normal! 
This is just my 2 cents about this particular type of deck. Until next 
time, happy Dueling.

Contact me at mxdelamar@yahoo.com