Just published an OSE version of much of the 5e science-fantasy content of this blog over on driveThruRpg.  Here is some supporting content for the Sorcerer class presented in that book.  Here is a Cold Prince Bloodline (Dolmenwood inspired) for the OSE Sorcerer class.

Bloodline: The Cold Prince

Your innate magic comes from fey blood, specifically the frost elves and even (maybe) the Cold Prince himself.  You gain the following innate traits with this bloodline:

• Any spell that is related to cold (for example, a spell that does cold damage) always has a 5 in 6 chance of working.
• Your spells work against any creature listed as an ally of the Cold Prince even where this violates normal immunities. For example, your charm spells work against banshees.

As you mature as a scion of the Cold Prince you unlock fey boons. At level 3, 7, 10, and 14 you may roll on the table below to see what sorcerous power you have gained (a generous referee may allow you to select an option if you roll the same one twice without benefit.)

1. Frigia: Your connection to the Cold Prince as the benefit that your body is inured to cold. You can stand zero degrees Fahrenheit without discomfort, even totally nude. Greater cold, such as that produced by a sword of cold, ice storm, cold wand, or white dragon’s breath, must be saved against. All saving throws against cold are made with a bonus of +3, and damage sustained is one-half (if the saving throw is not made) or one-quarter (if the saving throw is made) of damage normal from that attack form. Gaining this trait multiple times allows you to grant this cold resistance to anyone you touch for 1 turn per level.
2. Fey Prescence: You are able to project a beguiling and fearsome presence. You have a 5 in 6 chance of casting the charm person
   • Rolling this boon a second time grants the spell charm monster.
   • Rolling this boon a third time guarantees you can cast either spell.
3. Misty Escape: For 1d4+level rounds, you fade from existence, becoming a mere shadow suspended between the faerie realms and the mortal lands. Your AC and saves improve by +1, and with a successful spell check (3-in-6), you turn invisible (as the spell). If you roll a 6, you delve too far into the Elflands of Frigia, vanishing into the faerie realms for 1d4 minutes, hours, days or weeks (determine randomly).
4. Ice King/Queen: The first time you gain this boon when in a frozen/arctic climate your spells become infused with the power of cold and you can add your CHA modifier to the damage of your spells. If you gain this trait a second time, you may also change the damage type of any energy-based spell to cold damage as part of casting it.  You can do this 1d4 times per day before you exhaust the elemental power in the area. Each time you use this ability the temperature immediately around you drops by 10 degrees. Rolling this boon an additional time has one of the following effects:
   • Elfin: If your skin isn’t snow white already, it is now.
   • Cold iron: You suffer one extra point of damage when hit with cold iron weapons.
5. Sub-Zero: You have access to the control weather spell, but only the Snow affect. You are not affected by the effects of this spell otherwise it acts as the control weather Your chance of casting this spell is a 5 in 6. Rolling this boon a second time grants the frost touch boon.
   • Frost touch: your touch inflicts 1d3 frost damage.
6. Beguiling Defense: You have Advantage on saving throws against being charmed (or similar effects). If a creature attempts to charm you, it instead must roll the relevant saving throw and if he fails, he comes under the effect of the spell as if you were the caster.
   • The second time you roll this boon, if your hair isn’t steel gray or light/white-blonde (your choice), it is now.
7. Forest Walk: You gain the ability to cast the druid spell pass plant with a 2-in-6 chance of success. For each time you gain this fey boon you increase the chance of success by 1 and increase the number of allies that can travel with you by 3. You also gain the snow-clad ground boon.
   • Snow-clad ground: Pass without leaving a trace.
8. Warhorn of Frigia: You sound a great war horn, calling the armies of Elfland to your side. Faithful unto death and fierce in battle, their tie to the mortal plane is but short and fleeting. The spell requires sounding a horn carved from a beast of 5 HD or greater. If the horn is set with precious jewels and metals (worth no less than 500 gp), the caster receives a +1 bonus to the Host of Frigia table. The horn must be held and sounded once every three rounds the spell is in effect (see below). Sounding the horn requires an action, and if the horn fails to be sounded, the spell comes to an end. The warriors’ bodies and kit vanish when slain or the spells ends. You may use this boon once per campaign and an additional use each time you gain this fey boon.

Host of Frigia

1. A group of 1d4+1 brownie (OSE Advanced Fantasy Referee’s Tome, pg. 28) slingers answer the call. Each is armed with a sling, a satchel of sling bullets, and a short sword, but vanishes after taking a single point of damage. The spell lasts for 1d6+level rounds, as long as the horn is sounded once every three rounds, or until all the fey are dismissed.
2. A body of 1d4+level trollish (OSE Advanced Fantasy Referee’s Tome, pg. 120) spearmen supported by 1d4+1 brownie slingers heed the call. The spearmen carry flashing long spears. Each ally vanishes after taking a single point of damage. The spell lasts for 1d8+level rounds, as long as the horn is sounded once every three rounds, or until all the fey are dismissed.
3. A rough band of 1d12+level trollish spearmen and 1d8+level brownie slingers answer the call. All vanish after taking a single point of damage. The spell lasts for 1d10+ level rounds, as long as the horn is sounded once every three rounds, or until all the fey are dismissed.
4. A troop of 2d8+level trollish spearmen, 1d8+level brownie slingers, and 1d8 hob footmen answer the call. The spell lasts for 1d12 rounds, as long as the horn is sounded once every three rounds, or until all the fey are dismissed.
5. A marauding force of 1d20+level trollish spearmen, 1d16+level brownie slingers, 1d12+level elven knights (use a noble from (OSE Advanced Fantasy Referee’s Tome, pg. 90), and1d10 pixie archers (OSE Advanced Fantasy Referee’s Tome, pg. 95) answer the summons. The spell lasts for 1d16 rounds, as long as the horn is sounded once every three rounds, or until all the fey are dismissed.
6. A thundering company of 2d12+level trollish spearmen, 1d20+level brownie slingers, 2d8+level elvish kngihts, 1d12+level pixie archers, and 1d8 fomorians (Use hill giants, OSE Advanced Fantasy Referee’s Tome, pg. 59) answer the summons. The spell lasts for 1d20 rounds, as long as the horn is sounded once every three rounds, or until all the fey are dismissed.
7. The caster’s call for aid is answered by the full host of Elfland. The spell lasts for 2d12+level rounds. Immediately re-roll the spell check to determine the type and number of fey that answer the call, re-rolling any results of 7+. As long as the caster continues to sound the horn, re-roll the spell check again every third round, as new allies answer the call.