SCHEDULE 13D

CUSIP No.

492327101

Name of reporting person

ADAR1 Capital Management, LLC

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

TEXAS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 5,389,264.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 5,389,264.00
10	Shared Dispositive Power 0.00

Aggregate amount beneficially owned by each reporting person

5,389,264.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

13.27 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

The amounts reported in boxes 7, 9 and 11 include (i) 4,391,237 shares of Common Stock held by ADAR1 Partners, LP, (ii) 743,358 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 254,669 shares of Common Stock held by ADAR1 SPV I, LP as of August 21, 2025. As the investment manager of ADAR1 Partners, LP and ADAR1 SPV I, LP and as the sub-advisor of Spearhead Insurance Solutions IDF, LLC, ADAR1 Capital Management, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, ADAR1 SPV I, LP and Spearhead Insurance Solutions IDF, LLC. Amounts reported do not include shares underlying certain swap arrangements as disclosed in the Schedule 13D. The percentage in box 13 is based on 40,615,414 shares of Common Stock of the Issuer outstanding as of July 31, 2025, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2025, filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No.

492327101

Name of reporting person

ADAR1 Capital Management GP, LLC

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

TEXAS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 4,645,906.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 4,645,906.00
10	Shared Dispositive Power 0.00

Aggregate amount beneficially owned by each reporting person

4,645,906.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

11.44 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

The amounts reported in boxes 7, 9 and 11 include (i) 4,391,237 shares of Common Stock held by ADAR1 Partners, LP and (ii) 254,669 shares of Common Stock held by ADAR1 SPV I, LP as of August 21, 2025. As the general partner of ADAR1 Partners, LP and ADAR1 SPV I, LP, ADAR1 Capital Management GP, LLC may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP and ADAR1 SPV I, LP. Amounts reported do not include shares underlying certain swap arrangements as disclosed in the Schedule 13D. The percentage in box 13 is based on 40,615,414 shares of Common Stock of the Issuer outstanding as of July 31, 2025, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2025, filed with the SEC on August 6, 2025.

SCHEDULE 13D

CUSIP No.

492327101

Name of reporting person

Daniel Schneeberger

Check the appropriate box if a member of a Group (See Instructions)

(a)

(b)

SEC use only

Source of funds (See Instructions)

Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)

Checkbox not checked

Citizenship or place of organization

TEXAS

Number of Shares Beneficially Owned by Each Reporting Person With:

7	Sole Voting Power 5,389,264.00
8	Shared Voting Power 0.00
9	Sole Dispositive Power 5,389,264.00
10	Shared Dispositive Power 0.00

Aggregate amount beneficially owned by each reporting person

5,389,264.00

Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)

Checkbox checked

Percent of class represented by amount in Row (11)

13.27 %

Type of Reporting Person (See Instructions)

Comment for Type of Reporting Person:

The amounts reported in boxes 7, 9 and 11 include (i) 4,391,237 shares of Common Stock held by ADAR1 Partners, LP, (ii) 743,358 shares of Common Stock held by Spearhead Insurance Solutions IDF, LLC and (iii) 254,669 shares of Common Stock held by ADAR1 SPV I, LP as of August 21, 2025. As the manager of ADAR1 Capital Management, LLC and ADAR1 Capital Management GP, LLC, Mr. Schneeberger may be deemed to indirectly beneficially own securities held by ADAR1 Partners, LP, Spearhead Insurance Solutions IDF, LLC, and ADAR1 SPV I, LP. Amounts reported do not include shares underlying certain swap arrangements as disclosed in the Schedule 13D. The percentage in box 13 is based on 40,615,414 shares of Common Stock of the Issuer outstanding as of July 31, 2025, reported in the Issuer's Quarterly Report on Form 10-Q for the quarterly period ended June 30, 2025, filed with the SEC on August 6, 2025.

SCHEDULE 13D

Item 1.

Security and Issuer

(a)

Title of Class of Securities:

Common Stock, $0.0001 par value per share

(b)

Name of Issuer:

Keros Therapeutics, Inc.

(c)

Address of Issuer's Principal Executive Offices:

1050 Waltham Street, Suite 302, Lexington, MASSACHUSETTS , 02421.

Item 1 Comment:

This Amendment No. 4 ("Amendment No. 4") amends and supplements the statement on Schedule 13D filed with the Securities and Exchange Commission on April 11, 2025 (as amended from time to time, the "Schedule 13D"). Except as otherwise stated, the Schedule 13D remains unchanged. Capitalized terms used herein and not otherwise defined in this Amendment No. 4 have the meanings set forth in the Schedule 13D.

Item 4.

Purpose of Transaction

On August 21, 2025, ADAR1 Capital Management issued a press release (the "August 21 Press Release"), including an open letter, expressing its disappointment with the Board's refusal to engage with ADAR1 Capital Management on the Issuer's strategy, capital allocation priorities and Board refreshment, and stating that it will seek to elect new directors at the next annual meeting of the Issuer's stockholders should the Board continue to refuse ADAR1 Capital Management's invitation to engage. The foregoing description of the August 21 Press Release does not purport to be complete and is qualified in its entirety by reference to the full text of the August 21 Press Release, which is attached hereto as Exhibit H and is incorporated herein by reference.

Item 5.

Interest in Securities of the Issuer

(a)

The information contained on the cover pages of this Amendment No. 4 is incorporated herein by reference.

(b)

The information contained on the cover pages of this Amendment No. 4 is incorporated herein by reference.

(c)

No transactions in the shares of Common Stock have been effected by the Reporting Persons during the past sixty (60) days.

Item 6.

Contracts, Arrangements, Understandings or Relationships With Respect to Securities of the Issuer

The Reporting Persons no longer hold the Long Puts and Short Puts previously reported in the Schedule 13D.

Item 7.

Material to be Filed as Exhibits.

Exhibit H: August 21 Press Release

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

ADAR1 Capital Management, LLC

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, Manager
Date:	08/21/2025

ADAR1 Capital Management GP, LLC

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger, Manager
Date:	08/21/2025

Daniel Schneeberger

Signature:	/s/ Daniel Schneeberger
Name/Title:	Daniel Schneeberger
Date:	08/21/2025