A frost themed Warden build, should be able to clear all the solo content with it and it should still fair well in dungeons even veteran ones, the empty slot is flex and could be filled with the Necromancer's Unnerving Graveyard.

Easy to get setup would be Iceheart / Icy Conjurer / Frostbite

This build also has some group utility with Ice Fortress, Northern Storm, Unstable Wall of Elements and could have more if using the Green Balance skill-line.

Extra info:
- if using Icy Conjurer maybe slot Fetcher Infection because of the minor debuff proc
- if not subclassing, Lotus Blossom from Green Balance could be used alongside the skill-line passives
- consider the Elemental Rage ultimate for big AoE burst, Frost Comet for single target engage
- if need of more self heal, consider the Polar Wind morph instead of Arctic Blast
- if lacking Magicka regen, could use Atronach mundus instead of Thief, trading some damage for regen
- Bird of Prey could be replaced by Inner Light if you want more crit and max Magicka, losing Minor Berserk
- consider any morph of Weakness to Elements, Elemental Drain applying Minor Magickasteal for sustain and Icy Conjurer proc, and Elemental Susceptibility applying Chilled
- if you don't have enough skill points, remove the food duration passives, the medium and heavy armor passives, the soul magic passives and any other passives you might not need
- for easy / group content you may not need Harness Magicka, replace it by anything you like or feel like you need
- instead of Siphoning Spells in the Fitness CP tree, you could use Bastion for better shields

Flex sets options are:
- Winterborn (Maelstrom Arena) -> AoE damage and crowd control
- Icy Conjurer (Dungeon - Frostvault) -> single target, procs on minor debuffs
- Frostbite (Overland - Blackwood) -> consistent 8% damage increase on Frost damage, further 4% on Chilled enemies and further 2% on ennemies with Minor Brittle which are all applied by this build
- Whorl of the Depths (Trial - Dreadsail Reef) -> Minor Slayer, solid AoE damage

Flex monster set options are:
- Iceheart (Dungeon - Direfrost Keep) -> survivability with frost damage in AoE while shield is up
- Nunatak (Imperial City) -> AoE damage with crowd control and applying Major Brittle

Race is Nord for roleplay and more survivability, Dark Elf / High Elf could be better for damage output but performance is not really the aim of this build.