FETOR uses OSRIC as it's base and the rules are available for free at http://www.lulu.com/shop/stewart-marshall/osric-a5-pdf/ebook/product-206...
-5 hit points is dead however honour dice can save you
All attributes have a % beside them but it's not necessary to add them until something alters an attribute or second level when attributes may start to rise.
Leveling: Each level attributes may rise 1d3-1% except one Prime requisite which gets 1d20-1%. Humans get an extra 1d30% on any attribute as well (on top of the 1d3-1 or 1d20-1). Items, magic, etc can alter this. Also, a character's Honour Die can be added to any attribute % when levels change (up or down ie undead drains).
Honour Dice: Each character has an Honour Die that can range from -1 through 1d30 based on attributes, level, and actions. An honour die can be used to suddenly get a second wind and add hit points, even to avoid death. It can also be used to add or subtract from any roll. Once used, it drops one level. If you go below 0, you start getting negative modifiers to all your rolls. Honour increases with deeds, especially deeds people see or at least hear about. [-1, 0, d1, d2, d3, d4, d6, d7, d8, d10, d12, d14, d16, d20, d24, d30] Having honour higher than 3*level can also cause issues by attracting unwanted attention from powerful beings who want to swat you like a bug for your hubris.
Fame Dice: The group gains fame as they travel and it has the same range as Honour Dice and can be used by any member of the group once per day. using it always drops the die one level.
Proteges: Every character has a Protege waiting for when they die. The player can choose to use the Protege at any reasonable point instead of their main character or they can wait until death. Protege's only accrue 35% of the main character's experience (maybe sending diaries back to them?). This takes effect when you create your Protege or die and do not have one. Unless stated otherwise, all character's have a Will that leaves their belongings to their Protege. The rest of the group is free to ignore the Will.
Reverberation Damage: When you kill (or knockout) any creature or character of a lower level than yourself (or during a critical hit regardless of level), any damage that takes the opponent below zero can be added to an adjacent opponent.
Criticals and Fumbles: A 1 rolled on a d20 is always a fumble and will roll on my private table that may change from time to time. A 20 on a d20 is almost always a hit (some exceptions that require multiple 20s) and if it's a hit, and rolls on the critical table. I will post those tables at some point.
Thieves and Assassins: The Thief abilities have been simplified into Backstab, Climb, Traps & Locks, Hear Noise, Stealth, Pockets, Read Languages. Noting that Find Traps, Remove Traps, and Open Locks are one skill (Traps & Locks or TnL). Move Quietly and Hide in Shadows are one skill (Stealth). These are all abilities anyone can perform untrained except Climb as Climb means sheer surfaces. Anyone can attempt normal climbs, but the Thief ability is for surfaces no normal person would try. I will probably run these abilities like skills ala d30. A first level Gnome Thief with average attributes would have 6 in 30 chance of using Stealth effectively. An untrained Gnome with average attributes would have a 1 in 30 chance to use Stealth effectively. Persistent and effective use of Thief skills by a non-Thief may allow for some increase in ability when levelling up, but very rarely to the expertise of a Thief and a non-Thief may only increase one Thief ability per level. When a Thief or Assassin levels up, they will be given points to distribute as they see fit instead of static raises in abilities.
Races and other Classes: I can at times be convinced to try new races and classes for play. Usually with NPCs first, but I figure exceptions happen and if you want something bad enough, we should be able to find a compromise, except when we can't and we just move on with the game. Races are already slightly different than the base rules as well as expanded upon. See Character Creation. Note specifically the Ilfs (Elf-like), Gnobbits, Oafs, and Pixies. Also note that some races have skills in place of the racial skills in the rulebook.
Other Skills: Beyond the Thief and racial skills there are others that may come up. Swimming is randomly applied when the character swims for the first time. 1d30 is rolled and that's the character's swimming skill that they need to roll equal to (for treading) or below (for swimming) to utilize. Like any other skill, it can be worked on to raise.
Experience: As you do things, you gain experience. At certain amounts, you level up. You can also expend experience (once expended, it is lost and you can not cause yourself to drop a level by expending which limits the amount you can expend) to raise skills, save yourself from death, increase honour, etc. Each expenditure is 2000*level+500.