The Skystrider is a very nimble spellsword, using both her natural dexterity, as well as a plethora of spells, shouts and enchantments to outmaneuovre her foes and ensure she always has the upper hand. While her foes attack with futility, unable to get into melee range and watching as she deftly evades every missile, the Skystrider is able to dish out alot of pain. Her weapons of choice are two swords, as well as Destruction magic, enchantments, and a mastery of the Thu'um. She is also adept in the use of Light Armor, infiltration, acrobatics (I'll come to this later), and more defensive magics such as Alteration and Restoration.
Race: No single race is critical for roleplay, and I chose an Altmer. The magicka boost is hugely helpful on a hybrid character, although almost all races will get some benefit from their skillset and racial abilities.
Stone: Fairly unimportant. I went with the leveling ones until I got some important perks and then rolled with the Lord Stone for the extra protection.
Stat Distribution: 1/1/1 in Health/Magicka/Stamina. If you're playing an Altmer, you can afford to put a few extra points into Health and Stamina.
One-handed:Your main offensive skill. It isn't too important what weapon you use, but I prefer swords for their balance between speed, reach and damage. You'll often be switching between 1-hand and dual-wielding. A Skystrider is a master duelist, and key perks include Armsman, Fighting Stance, Dual Flurry, and Dual Savagery.
Destruction:Your secondary offensive skill. A Skystrider commands the powers of, well, the sky, and thus uses both Frost and Shock magic. However, Frost magic is primarily used to slow enemies, which makes Frostbite a very good spell. All Frost magic slows enemies by 50% for a few seconds, regardless of the damage dealt. This also makes Frost Cloak very useful at higher levels. However, many enemies in Skyrim are highly resistant to Frost, but hardly anything is resistant to Shock. You only really need up to Adept Destruction in here.
Restoration:The Skystrider can use the powers of Restoration to heal her wounds and protect herself from spellcasters. She can also use it to keep herself strong during battle, so that she's never unable to perform a power attack. Wards, in my opinion, are highly underrated. I can use the novice-level ward to block the breath attack of a level 30 dragon, and with the Ward Absorb perk, I can do this almost indefinetely. Key perks are up to Apprentice Restoration, Ward Absorb, Respite, and Regeneration.
Smithing:The Skystrider prefers to forge her own equipment. While she is no master smith, she knows the ins and outs of both Steel and Elven materials. These two materials can get you through pretty much the entire game - a full set of Elven with a Gilded Elven cuirass is just as strong as a full set of Scaled, and Elven and Steel weapons are very light (relatively speaking), meaning they drain less Stamina per hit, while still doing decent damage.
Enchanting:The Skystrider also enchants her own equipment, to improve upon her natural abilites. Important perks at lower levels are just ranks in Enchanter, although around level 40 you will want to work your way up the Armor side into Extra Effect.
Sneak:While not a true assassin, the Skystrider's light foot and natural dexterity make her a proficient infiltrator. The main reason for perks in Sneak is for the Silent Roll perk. It is actually very useful for dodging heavy attacks of many enemies, such as dual-wield and two-handed power attacks, giants, and some missile attacks like spells and arrows. Key perks are just up the left to Silent Roll.
Light Armor: Basic protection. While the focus is on not getting hit, Elven Armor is almost weightless and provides a moderate amount of protection. Key perks are around the left side of the tree all the way to the top, and you really only need 1 rank in Agile Defender.
Alteration:The Skystrider can use Alteration for a myriad of purposes - from basic protection, to waterbreathing, detection and light. Flesh spells don't have to be 'always on' if you're able to evade their strikes in the first place. Key perks are up to Adept and Magic Resistance, and further on to Atronach at high levels.
Weapons/Armor:Elven armor (with Gilded cuirass) and either Steel or Elven weapons. I know alot of people hate the look of the Elven Sword (I was using the Weapon Variant Expansion mod that adds a version that looks like the greatsword), so Skyforge Steel weapons, Scimitars and Blades Swords work well too, as they have the same damage value.
Enchantments:A very important note is to note enchant the weapon you're going to use in your offhand. I enchanted my main hand weapon with 2 points of Frost Damage, exclusively for the slow. With enchanting at about 50 and 3 points in the Enchanter perk, it has over 2000 uses. Ring - Resist Magic, Amulet of Talos (shouts are very important, will discuss later), Armor - Health, Helmet - Magicka, Gauntlets - One-handed damage, Boots - Stamina.
There isn't really any roleplay set out for you, it would really depend on your race. I think the skillset gravitates towards the 'good' side of things though, and the emphasis on Shouts could mean you craft your RP experience around the main quest. My character was an Altmer woman who learned about her natural proficiency in the Thu'um at an early age, but kept it a secret. She was trained in the arts of the sword and spell, and escaped to Skyrim to seek her destiny and learn more about the mysterious power of the Voice.
Requires: Become Ethereal
With a Shout the Skystrider enters her Air Form, able to pass through attacks without harm, and glide effortlessly across the battlefield. This can be used to charge a vastly superior enemy (such as a powerful mage for instance) without harm, and strike on your terms.
Novice - Serenity:
Requires: Altmer, Slow Time
The Slow Time shout doesn't affect your rate of Magicka regeneration. Using this with the Altmer's Highborn ability is incredibly useful in tight combat situations, to regain magicka very quickly in real time.
Requires: Elemental Fury
A shout commands the air around the Skystrider, allowing her to attack much more quickly. Equipping an unenchanted weapon in her offhand, the air enhances the weapon, and she flies into a whirlwind of blows. When performing a dual-wield power attack, the game only checks the attack speed of your left-hand weapon. This means you can have an enchanted weapon in your right hand and still get the attack speed boost with dual power attacks. After running out of Stamina, attack normally with your offhand weapon for the rest of the duration.
Requires: Whirlwind Sprint, Ice Storm
The Skystrider creates a whirlwind of freezing air, and launches it at her foes. At the same time, she uses a Shout to launch herself alongside it, striking simultaneously for a massive burst of damage. To do this, walk backwards while casting Ice Storm in your left hand and a sword equipped in your right. Walking backwards causes the storm to travel slower. Then use Whirlwind Sprint and you should hit your foe at the same time the Ice Storm arrives.
Expert - Wind Whisper:
Requires: Detect Life, Ice Storm
The winds whisper to the Skystrider, revealing the locations of others in the area. She can then send a chilling response, gaining the attention of an enemy from out of sight. While testing I discovered you can shoot Ice Storm through walls! While the storm itself doesn't do any damage, the trails it leaves on the ground do! This means you can 'pull' enemies from the other side of walls that wouldn't be able to see or hear you normally. You can use Detect Life to line up your shot.
Combat Notes (Video):
Combat for the Skystrider varies greatly between different types of opponents. Ranged or mage enemies you'll want to close on right away with Become Ethereal or Whirlwind Sprint, while with melee enemies you might want to use a Flesh spell followed by Frost Breath. Frost Breath, in my opinion, is a highly underrated shout. It staggers, deals a little damage over time, and slows down the enemies it affects. This is ideal for when you need to heal or want to use ranged magic. In melee combat, you should remember to use Frostbite lots. It's very magicka-friendly, and slows the enemy just as much as a bigger spell. This allows you to move in when you want to, not when the enemy comes to you. At higher levels you can use Ice Spike for the same effect, now that your magicka pool is larger. You should also use Silent Roll to dodge alot, as it is ideal for evading missile attacks and heavy melee attacks. A quick roll away from an enemy can save you a whole lot of pain. It's very easy to do on PC but I'm not sure how the buttons are positioned on console. Also, wards. Don't forget to use them! You can completely block a dragon's breath attack with the most basic of wards. The Skyblade special move is also very useful when dealing with tougher enemies.
You might be a little confused by the use of both the spellsword style and dual wielding. Since changing your offhand takes a negligible amount of time, don't underestimate the power a few dual power attacks can give you if used at the opportune time. You should stay as a mobile spellsword until a perfect opportunity arises (enemy misses power attack, gets staggered, etc), and then go in with a storm of strikes.
You should be able to see most of that in practice in my demonstration video.
Sample 30 Perk Build:
180 (+50) Magicka | 200 Health | 210 Stamina (264 | 234 | 243 Modified)
Armsman 3, Dual Flurry 1, Dual Savagery, Fighting Stance
Novice - Adept Destruction
Novice - Apprentice Restoration, Respite, Regeneration, Ward Absorb
Steel, Elven Smithing
Novice - Adept Alteration, Magic Resistance 1
Stealth 1, Muffled Movement, Light Foot, Silent Roll
Agile Defender 1, Custom Fit, Unhindered