Free Agent - Unknown
My fav build for arena, getting a sneaky kill procs shadowdrinker's passive allowing you to become invisible again. It has 30% cd, 35 flat pen to erase squishies, 20% pen for tankier enemies and some movement speed + extra with jotunn's vigor.
Brawler's beat stick is a personal preference, as antihealing is always useful for either heals or lifesteal. Transcendence is an option if you want the stacks route, as it offers more damage but takes time to get there (I'm not the biggest fan for arena). Feel free to slap there whatever you like, serrated edge, arondight, or even a survivability item if needed.
Bluestone Brooch
PASSIVE - Enemies hit by your damaging abilities take an additional 160 Physical Damage over 2s. Enemy gods take an additional 10% of their Current Health as Physical Damage over 2s. Subsequent hits on the same target do half the bonus damage for the next 3s.
Jotunn's Vigor
GLYPH - If you drop beneath 60% health, gain 15% Movement Speed and 30% Physical Ability Lifesteal for 8s. This effect may only occur once every 15s.
Shadowdrinker
PASSIVE - Killing an enemy god drains their shadow, causing you to enter stealth and gain 30% Movement Speed for 5s. Taking damage, firing an Ability, or firing a Basic Attack breaks the stealth.
Hydra's Lament
PASSIVE - For 8s after using an ability, your next Basic Attack will deal an additional 25% damage. Abilities that function like basic attacks do not benefit from this. PASSIVE - This item grants 2.5 MP5 per 10% of your missing Mana.
Brawler's Beat Stick
PASSIVE - Enemies hit by your Abilities have 40% reduced healing for 5 seconds. Getting a kill or assist on an enemy god creates a field that lasts 10s, providing allies within it 20 Power + 2 Per level. This effect can only occur once every 10 seconds.
Heartseeker
PASSIVE - Your abilities deal an additional 2% of the targets maximum Health as Physical Damage. If you have over 150 Physical Power, your ability bonus damage scales up. This effect reaches a maximum of 6% Maximum Health damage at 250 Physical Power. Subsequent hits on the same target do 75% of the bonus damage for the next 3s.
Temporal Beads
Using this item removes Crowd Control Effects and makes you immune to new ones for 2s. Additionally, your active cooldowns are reduced by 3s on use. Cooldown - 140s.
Scorching Blink Rune
Using this item will allow you to teleport up to 45 units away instantly, leaving behind a trail of wildfire that burns Enemies that pass through it for 20 (+ 4 per level) True Damage every 0.5s for the next 4s. Additionally, enemies hit have their Movement and Attack Speed Slowed by 15%. These effects persist for 1.5s after leaving the flames. This item can not be used if you have taken or dealt damage in the last 3s. Cooldown - 120s.