Free Agent - Unknown
I'd go with bumba's even on casual modes like arena, as its stats are great.
Bumba's Spear
PASSIVE - Your Basic Attacks deal +50 True Damage and your Abilities deal +35% damage against Jungle Camps and Jungle Bosses. When you kill any of these you gain a 10% power buff for 30s and are healed for 8% of their Health, 10% of your Mana.
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.
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.
Y10 Evolved Transcendence
PASSIVE - You gain Physical Power equal to 2% of your Maximum Mana.
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.
Y10 Serrated Edge
PASSIVE - For every non-ultimate ability on cooldown you gain a stack of Cruelty. Each stack provides 7 Physical Power and 2% Physical Lifesteal.
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.