A Fiery Descent into the Fallen Heart Flame Arc
Battle Through the Heavens (also known as Doupo Cangqiong or Fights Break Sphere), the acclaimed donghua adaptation of Heavenly Silkworm Potato’s iconic xianxia web novel, continues its fifth season with episode 170, released on October 25, 2025. This ongoing “yearly edition” (nianban) season, produced by Motion Magic and streaming on platforms like Tencent Video and iQIYI, has kept fans hooked with its blend of intense cultivation battles, intricate alchemy, and Xiao Yan’s unyielding quest for power. Episode 170 marks a pivotal moment in the “Fallen Heart Flame” arc, ramping up the tension as Xiao Yan delves deeper into the perilous heart of Jia Nan Academy’s Qi Refining Tower. Below, we break down the episode’s plot, key moments, character developments, and fan reactions, while avoiding major spoilers for those catching up.
Episode Context and Setup
To appreciate episode 170’s stakes, a quick recap: Season 5 picks up after the climactic “Three-Year Agreement” duel with Nalan Yanran, where Xiao Yan triumphs over the Misty Cloud Sect’s prodigy and begins his journey toward greater heights. Reunited with his childhood love Xun’er at Jia Nan Academy, Xiao Yan establishes the Pan Gate faction, forging alliances with friends like Wu Hao and Hu Jia. His ultimate goal remains avenging his father by confronting the Yunlan Sect, but to do so, he must refine his Dou Qi and master rarer Heavenly Flames—ethereal fires that amplify an alchemist’s prowess.
The Qi Refining Tower, a cornerstone of the academy, channels geothermal energy from the subterranean Fallen Heart Flame (the 19th-ranked Heavenly Flame). This flame isn’t just a power source; it’s a sentient entity, born from eons of accumulated essence, capable of devouring cultivators whole. 1 Episodes leading into 170 see Xiao Yan, guided by his ring-bound mentor Yao Lao, preparing for a high-risk submersion. Having already subdued the Green Lotus Core Flame, Xiao Yan now eyes this more intelligent and volatile force, setting the stage for a trial that tests not just his body, but his very soul.
Plot Summary
Warning: Mild spoilers ahead for episode 170—proceed if you’ve watched up to 169.
Episode 170, titled something akin to “Descent into the Inferno” in fan translations (official Chinese title: “陨落心炎之渊” or “Abyss of the Fallen Heart Flame”), clocks in at around 24 minutes and delivers a masterclass in escalating dread and visual spectacle. The episode opens with Xiao Yan finalizing his preparations atop the Qi Refining Tower, the academy’s elite students buzzing with rumors of his audacious plan. Xun’er, ever the steadfast supporter, shares a poignant moment with him, her ancient Gu Clan heritage subtly hinting at the cosmic dangers ahead—flames like this could unravel even a prodigy like Xiao Yan.
As the tower’s barriers seal, Xiao Yan activates his Flame Mantra technique, channeling his existing flames to shield against the encroaching heat. The descent begins: layer by layer, he plunges into the tower’s underbelly, where the air thickens into a mirage of crimson illusions. The animation here shines, with swirling vortices of fire serpents—ethereal guardians of the flame—lashing out in fluid, particle-heavy sequences that evoke the raw fury of a volcano’s core. 0 These aren’t mere visuals; they’re narrative tools, manifesting Xiao Yan’s inner doubts as hallucinatory beasts that force him to confront past failures, from his crippled Dou Qi days to the sting of clan betrayals.
Mid-episode builds unbearable suspense as Xiao Yan reaches the flame’s outer shell. The Fallen Heart Flame, depicted as a colossal, pulsating heart wreathed in invisible, soul-searing tendrils, awakens with a roar that shakes the tower above. Unlike the more primal Green Lotus Flame, this one possesses rudimentary intelligence, probing Xiao Yan’s mind like a predator sizing up prey. 1 Yao Lao’s ethereal voice urges restraint, but Xiao Yan’s trademark defiance kicks in—he deploys a daring alchemy formation to siphon the flame’s essence, blending strategy with sheer willpower. A brief flashback interlude to his training montage underscores his growth, reminding viewers of the alchemical genius who’s come so far from Wu Tan City’s “waste.”
The climax erupts in a symphony of flame clashes: Xiao Yan’s Bone-Chilling Flame collides with the heart flame’s invisible waves, creating shockwaves that ripple through the tower and alert the academy’s elders. Without revealing the outcome, the episode ends on a heart-pounding cliffhanger, teasing the flame’s counterattack and hinting at reinforcements from above. It’s a bottle-episode masterpiece, focusing inward on Xiao Yan’s isolation while the world above teeters on intervention.
Key Moments and Visual Highlights
- The Descent Sequence: A standout 5-minute segment where Xiao Yan navigates the tower’s pressure layers. The 3D animation, enhanced in this season’s 4K release, uses dynamic camera angles and heat-distortion effects to convey claustrophobia and intensity. 2 Fans have compared it to the volcanic dives in Perfect World, but with a more psychological edge.
- Illusionary Assault: The flame’s mind games manifest as spectral foes, including echoes of Nalan Yanran and his father. This ties back to season 4’s emotional beats, adding layers to Xiao Yan’s arc.
- Yao Lao’s Intervention: A subtle mentor moment where the old alchemist imparts a cryptic tip on “taming the untamable,” foreshadowing Xiao Yan’s evolution toward Dou Wang-level prowess.
- Cliffhanger Tease: The final shot—a serpent of invisible flame coiling toward Xiao Yan—mirrors the season’s promotional art, leaving viewers desperate for episode 171’s preview. 3
The episode’s pacing is deliberate, clocking in slower than the tournament arcs but building to a fever pitch that rewards patient viewers. Sound design amplifies the immersion: the low rumble of subterranean fires blends with Xiao Yan’s labored breaths, scored by a tense orchestral swell laced with traditional guzheng strings.
Character Developments
Episode 170 is Xiao Yan-centric, but ripples affect the ensemble:
- Xiao Yan: His resolve hardens, but cracks show— the flame’s illusions expose vulnerabilities, humanizing the prodigy who’s often portrayed as unflappable. This episode subtly advances his alchemy mastery, hinting at a new pill-refining breakthrough.
- Xun’er: Her brief appearance reinforces her role as emotional anchor, with a knowing glance suggesting she senses the peril through her clan’s bloodline.
- Yao Lao: More mentor than fighter here, his guidance feels urgent, foreshadowing potential sacrifices in the arc’s latter half.
- Supporting Cast: Academy figures like Su Qian (the Great Elder) react to the tower’s tremors, setting up external conflicts for future episodes. No major appearances from rivals like Han Feng yet, but the groundwork is laid.
This installment deepens the theme of isolation in cultivation: power comes at the cost of solitude, a xianxia staple that Battle Through the Heavens executes with nuance.
Fan Reactions and Community Buzz
Since its release yesterday (October 25, 2025), episode 170 has lit up X (formerly Twitter) and Reddit’s r/Donghua. Posts from accounts like @idnflixofficial and @KurinaOfficial shared previews and links, garnering hundreds of views overnight. 22 20 Fans praise the animation’s fidelity to the novel’s chapter 500-ish events, with one X user noting, “That heart flame reveal gave me chills—Motion Magic nailed the sentience!” 21 A YouTube breakdown video titled “BTTH Season 5 Ep 170 – Story Breakdown & Surprising Twists! Dou Sheng Retreat!” racked up views, dissecting the “Dou Sheng” (high-level cultivator) implications teased in the illusions. 6
Critiques focus on pacing—some felt the descent dragged compared to season 4’s flashier fights—but overall reception is positive, with MyAnimeList scores for the season hovering at 8.2/10. Chinese forums like Bilibili echo this, hailing it as a “return to form” after mid-season filler concerns. Multilingual subs (English, Indonesian, Spanish) on sites like Lucifer Donghua and DonghuaStream have broadened access, fueling global hype. 1 7
Where to Watch and Next Steps
Catch episode 170 in 4K with multi-subtitles on platforms like:
- Tencent Video or iQIYI (premium for ad-free, official subs).
Episode 171 (preview already out) promises the taming attempt’s fallout, with potential cameos from Pan Gate allies. If you’re new, start from season 1— the full series now exceeds 300 episodes across seasons.
Episode 170 exemplifies why Battle Through the Heavens endures: it’s not just about flames and fights, but the inner forge that tempers a hero. Xiao Yan’s descent isn’t mere plot progression; it’s a metaphor for every cultivator’s (and viewer’s) plunge into the unknown. What flames will you face next? Tune in and find out.
