Generally, you don't want to pay more than one mana for a burn spell, especially one that's a sorcery, making Chain Lightning the perfect mana cost

Iroas, God of Victory (Commander Catchup, Journey into Nyx Edition) Kurkesh, Onakke Ancient (Ghost in the Machines) Jalira, Master Polymorphist (JaliraPOW!) Mishra, Artificer Prodigy (Possibility Storm Shenanigans) Yisan, the Wanderer Bard (All-in Yisan) Selvala, Explorer Returned (Everyone Draws Lots!) Grenzo, Dungeon Warden (Cleaning Out the Cellar) Karona, False God (God Pack) Doran, the Siege Tower (All My Faves in One Deck!) Karador, Ghost Chieftain (my Magic Online deck) Karador, Ghost Chieftain (Shadowborn Apostles & Demons) King Macar, the Gold-Cursed (GREED!) Niv-Mizzet, the Firemind ( Chucks somewhat vicious deck) Roon of the Hidden Realm (Mean Roon) Skeleton Ship (Fun with -1/-1 counters) Vorel of the Hull Clade (Never Trust the Simic) Anax and Cymede (Heroic Co-Commanders) Aurelia, the Warleader ( plus Hellkite Tyrant shenanigans) Borborygmos Enraged (69 land deck) Bruna, Light of Alabaster (Aura-centric Voltron) Damia, Sage of Stone ( Ice Cauldron shenanigans) Emmara Tandris (No Damage Tokens) Gahiji, Honored One (Enchantment Ga-hijinks) Geist of Saint Traft (Voltron-ish) Ghave, Guru of Spores ( Melira Combo) Glissa Sunseeker (death to artifacts!) Glissa, the Traitor ( undying artifacts!) Grimgrin, Corpse-Born (Necrotic Ooze Combo) Jeleva, Nephalias Scourge ( Suspension of Disbelief) Johan (Cat Breath of the Infinite) Jor Kadeen, the Prevailer (replacing Brion Stoutarm in Mo Myrs) Karona, False God (Vows of the False God) Lord of Tresserhorn (ZOMBIES!) Marath, Will of the Wild ( Wild About +1/+1 Counters) Melira, Sylvok Outcast ( combo killa) Mirko Vosk, Mind Drinker ( Outside My Comfort Zone with Milling ) Nefarox, Overlord of Grixis (evil and Spike-ish) Nicol Bolas (Kicking it Old School) Nylea, God of the Hunt ( Devoted to Green) Oloro, Ageless Ascetic (Life Gain) Oona, Queen of the Fae (by reader request) Phage the Untouchable ( actually casting Phage from Command Zone!) Polukranos, World Eater (Monstrous!) Progenitus ( Fist of Suns and Bringers ) Reaper King (Taking Advantage of the new Legend Rules) Riku of Two Reflections ( steal all permanents with Deadeye Navigator + Zealous Conscripts ) Roon of the Hidden Realm ( Strolling Through Value Town) Ruhan of the Fomori (lots of equipment and infinite attack steps) Savra, Queen of the Golgari ( Demons) Shattergang Brothers (Breaking Boards) Sigarda, Host of Herons ( Equipment-centric Voltron) Skullbriar, the Walking Grave ( how big can it get?) Sliver Overlord (Featuring the new M14 Slivers!) Thelon of Havenwood ( Campfire Spores) Varolz, the Scar-Striped (scavenging goodness) Vorosh, the Hunter ( proliferaTION)

(Artifacts, legendaries, and Sagas are historic.) The second mode of What Must Be Done cares about what the characteristics of the returned permanent will be when it's on the battlefield, taking into account static abilities that would change its types
Doesn't that mean you shouldn't risk losing it in combat
Freerunning is a new mechanic introduced that offers an alternate casting cost for a card if youve dealt damage to player this turn with an assassin or your commander